Best sql plsql material

INTRODUCTION
SQL is divided into the following
1 Data Definition Language (DDL)
1 Data Manipulation Language (DML)
1 Data Retrieval Language (DRL)
1 Transaction Control Language (TCL)
1 Data Control Language (DCL)
DDL -- create, alter, drop, truncate, rename
DML -- insert, update, delete
DRL -- select
TCL -- commit, rollback, savepoint
DCL -- grant, revoke
CREATE TABLE SYNTAX
Create table <table_name> (col1 datatype1,
col2 datatype2 …coln datatypen);
Ex:
SQL> create table student (no number (2),
name varchar (10), marks number (3));
INSERT
This will be used to insert the records into
table.
We have two methods to insert.

1 By value method
1 By address method
a) USING VALUE METHOD
Syntax:
insert into <table_name> values
(value1, value2, value3 …. Valuen);
Ex:
SQL> insert into student values (1, ’sudha’,
100);
SQL> insert into student values (2,
’saketh’, 200);
To insert a new record again you have to
type entire insert command, if there are lot of
records this will be difficult.
This will be avoided by using address
method.
b) USING ADDRESS METHOD

Syntax:
insert into <table_name) values (&col1,
&col2, &col3 …. &coln);
This will prompt you for the values but for
every insert you have to use forward slash.
Ex:
SQL> insert into student values (&no,
'&name', &marks);
Enter value for no: 1
Enter value for name: Jagan
Enter value for marks: 300
old 1: insert into student values(&no,
'&name', &marks)
new 1: insert into student values(1,
'Jagan', 300)
SQL> /
Enter value for name: Naren
Enter value for marks: 400

old 1: insert into student values(&no,
'&name', &marks)
new 1: insert into student values(2,
'Naren', 400)
c) INSERTING DATA INTO SPECIFIED COLUMNS
USING VALUE METHOD
Syntax:
insert into <table_name)(col1, col2, col3
… Coln) values (value1, value2, value3 ….
Valuen);
Ex:
SQL> insert into student (no, name) values
(3, ’Ramesh’);
(4, ’Madhu’);
d) INSERTING DATA INTO SPECIFIED
COLUMNS USING ADDRESS METHOD
Syntax:
insert into <table_name)(col1, col2, col3

… coln) values (&col1, &col2 ….&coln);
This will prompt you for the values but for
every insert you have to use forward slash.
Ex:
(&no, '&name');
Enter value for name: Visu
old 1: insert into student (no, name)
values(&no, '&name')
new 1: insert into student (no, name)
values(5, 'Visu')
SQL> /
Enter value for name: Rattu
old 1: insert into student (no, name)
values(&no, '&name')
new 1: insert into student (no, name)
values(6, 'Rattu')
SELECTING DATA

Syntax:
Select * from <table_name>; -- here *
indicates all columns
or
Select col1, col2, … coln from
<table_name>;
Ex:
SQL> select * from student;
NO NAME MARKS
--- ------ --------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400
3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select no, name, marks from student;

NO NAME MARKS
--- ------ --------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400
3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select no, name from student;
NO NAME
--- -------
1 Sudha
2 Saketh
1 Jagan
2 Naren
3 Ramesh
4 Madhu
5 Visu

6 Rattu
CONDITIONAL
SELECTIONS AND OPERATORS
We have two clauses used in this
1 Where
1 Order by
USING WHERE
Syntax:
select * from <table_name> where
<condition>;
the following are the different types of
operators used in where clause.
1 Arithmetic operators
1 Comparison operators
1 Logical operators
1 Arithmetic operators -- highest
precedence

+, -, *, /
2 Comparison operators
Ø =, !=, >, <, >=, <=, <>
2 between, not between
3 in, not in
2 null, not null
2 like
3 Logical operators
3 And
4 Or -- lowest precedence
3 not
a) USING =, >, <, >=, <=, !=, <>
Ex:
SQL> select * from student where no = 2;
NO NAME MARKS
--- ------- ---------
2 Saketh 200
2 Naren 400
SQL> select * from student where no < 2;

NO NAME MARKS
--- ------- ----------
1 Sudha 100
1 Jagan 300
SQL> select * from student where no > 2;
NO NAME MARKS
--- ------- ----------
3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select * from student where no <=
2;
NO NAME MARKS
--- ------- ----------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400

SQL> select * from student where no >=
2;
NO NAME MARKS
--- ------- ---------
2 Saketh 200
2 Naren 400
3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select * from student where no !=
2;
NO NAME MARKS
--- ------- ----------
1 Sudha 100
1 Jagan 300
3 Ramesh
4 Madhu
5 Visu

6 Rattu
SQL> select * from student where no <>
2;
NO NAME MARKS
--- ------- ----------
1 Sudha 100
1 Jagan 300
3 Ramesh
4 Madhu
5 Visu
6 Rattu
b) USING AND
This will gives the output when all the
conditions become true.
Syntax:
select * from <table_name> where
<condition1> and <condition2> and ..
<conditionn>;
Ex:

SQL> select * from student where no = 2
and marks >= 200;
NO NAME MARKS
--- ------- --------
2 Saketh 200
2 Naren 400
c) USING OR
This will gives the output when either of the
condition becomes true.
Syntax:
Select * from <table_name> where
<condition1> and <condition2> or..
<condition>;
Ex:
SQL> select * from student where no = 2
or marks >= 200;
NO NAME MARKS
--- ------- ---------
2 Saketh 200

1 Jagan 300
2 Naren 400
d) USING BETWEEN
This will gives the output based on the
column and its lower bound, upper bound.
Syntax:
select * from <table_name> where <col>
between <lower bound> and <upper bound>;
Ex:
SQL> select * from student where marks
between 200 and 400;
NO NAME MARKS
--- ------- ---------
2 Saketh 200
1 Jagan 300
2 Naren 400
e) USING NOT BETWEEN

column which values are not in its lower bound,
upperbound.
Syntax:
not between <lower bound> and <upper
bound>;
Ex:
not between 200 and 400;
NO NAME MARKS
--- ------- ---------
1 Sudha 100
f) USING IN
column and its list of values specified.
Syntax:
in ( value1, value2, value3 … valuen);
Ex:
SQL> select * from student where no in

(1, 2, 3);
NO NAME MARKS
--- ------- ---------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400
3 Ramesh
g) USING NOT IN
This will gives the output based on the column
which values are not in the list of values
specified.
Syntax:
not in ( value1, value2, value3 … valuen);
Ex:
SQL> select * from student where no not
in (1, 2, 3);
NO NAME MARKS
--- ------- ---------
4 Madhu
5 Visu

6 Rattu
h) USING NULL
This will gives the output based on the null
values in the specified column.
Syntax:
is null;
Ex:
is null;
NO NAME MARKS
--- ------- ---------
3 Ramesh
4 Madhu
5 Visu
6 Rattu
i) USING NOT NULL

This will gives the output based on the not
null values in the specified column.
Syntax:
is not null;
Ex:
is not null;
NO NAME MARKS
--- ------- ---------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400
j) USING LIKE
This will be used to search through the rows
of database column based on the pattern you
specify.
Syntax:

like <pattern>;
Ex:
i) This will give the rows whose marks are
100.
SQL> select * from student where
marks like 100;
NO NAME MARKS
--- ------- ---------
1 Sudha 100
ii) This will give the rows whose name
start with ‘S’.
name like 'S%';
NO NAME MARKS
--- ------- ---------
1 Sudha 100
2 Saketh 200

iii) This will give the rows whose name
ends with ‘h’.
name like '%h';
NO NAME MARKS
--- ------- ---------
2 Saketh 200
3 Ramesh
iV) This will give the rows whose name’s
second letter start with ‘a’.
name like '_a%';
NO NAME MARKS
--- ------- --------
2 Saketh 200
1 Jagan 300
2 Naren 400
3 Ramesh

4 Madhu
6 Rattu
V) This will give the rows whose name’s
third letter start with ‘d’.
name like '__d%';
NO NAME MARKS
--- ------- ---------
1 Sudha 100
4 Madhu
Vi) This will give the rows whose name’s
second letter start with ‘t’ from ending.
name like '%_t%';
NO NAME MARKS
--- ------- ---------
2 Saketh 200
6 Rattu

Vii) This will give the rows whose name’s
third letter start with ‘e’ from ending.
name like '%e__%';
NO NAME MARKS
--- ------- ---------
2 Saketh 200
3 Ramesh
Viii) This will give the rows whose name
cotains 2 a’s.
name like '%a% a %';
NO NAME MARKS
--- ------- ----------
1 Jagan 300
* You have to specify the patterns in like using
underscore ( _ ).

USING ORDER BY
This will be used to ordering the columns data
(ascending or descending).
Syntax:
Select * from <table_name> order by
<col> desc;
By default oracle will use ascending order.
If you want output in descending order you
have to use desc keyword after the column.
Ex:
SQL> select * from student order by no;
NO NAME MARKS
--- ------- ---------
1 Sudha 100
1 Jagan 300
2 Saketh 200s
2 Naren 400

3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select * from student order by no
desc;
NO NAME MARKS
--- ------- ---------
6 Rattu
5 Visu
4 Madhu
3 Ramesh
2 Saketh 200
2 Naren 400
1 Sudha 100
1 Jagan 300
USING DML
USING UPDATE
This can be used to modify the table data.

Syntax:
Update <table_name> set <col1> = value1,
<col2> = value2 where <condition>;
Ex:
SQL> update student set marks = 500;
If you are not specifying any condition this
update entire table will.
SQL> update student set marks = 500
where no = 2;
SQL> update student set marks = 500,
name = 'Venu' where no = 1;
USING DELETE
This can be used to delete the table data
temporarily.
Syntax:
Delete <table_name> where <condition>;
Ex:

SQL> delete student;
If you are not specifying any condition this
will delete entire table.
SQL> delete student where no = 2;
USING DDL
USING ALTER
This can be used to add or remove columns and
to modify the precision of the datatype.
a) ADDING COLUMN
Syntax:
alter table <table_name> add <col
datatype>;
Ex:
SQL> alter table student add sdob date;

b) REMOVING COLUMN
Syntax:
alter table <table_name> drop <col
datatype>;
Ex:
SQL> alter table student drop column
sdob;
c) INCREASING OR DECREASING PRECISION
OF A COLUMN
Syntax:
alter table <table_name> modify <col
datatype>;
Ex:
SQL> alter table student modify marks
number(5);
* To decrease precision the column
should be empty.

d) MAKING COLUMN UNUSED
Syntax:
alter table <table_name> set unused
column <col>;
Ex:
SQL> alter table student set unused
column marks;
Even though the column is unused still it
will occupy memory.
d) DROPPING UNUSED COLUMNS
Syntax:
alter table <table_name> drop unused
columns;
Ex:
SQL> alter table student drop unused
columns;
* You can not drop individual unused
columns of a table.

e) RENAMING COLUMN
Syntax:
alter table <table_name> rename column
<old_col_name> to <new_col_name>;
Ex:
SQL> alter table student rename column
marks to smarks;
USING TRUNCATE
This can be used to delete the entire table data
permanently.
Syntax:
truncate table <table_name>;
Ex:
SQL> truncate table student;
USING DROP
This will be used to drop the database object;

Syntax:
Drop table <table_name>;
Ex:
SQL> drop table student;
USING RENAME
This will be used to rename the database
object;
Syntax:
rename <old_table_name> to
<new_table_name>;
Ex:
SQL> rename student to stud;

USING TCL
USING COMMIT
This will be used to save the work.
Commit is of two types.
1 Implicit
1 Explicit
a) IMPLICIT
This will be issued by oracle internally in
two situations.
1 When any DDL operation is performed.
1 When you are exiting from SQL * PLUS.
b) EXPLICIT
This will be issued by the user.

Syntax:
Commit or commit work;
* When ever you committed then the
transaction was completed.
USING ROLLBACK
This will undo the operation.
This will be applied in two methods.
1 Upto previous commit
1 Upto previous rollback
Syntax:
Roll or roll work;
Or
Rollback or rollback work;
* While process is going on, if suddenly power
goes then oracle will rollback the transaction.
USING SAVEPOINT
You can use savepoints to rollback portions of
your current set of transactions.

Syntax:
Savepoint <savepoint_name>;
Ex:
SQL> savepoint s1;
SQL> insert into student values(1, ‘a’, 100);
SQL> savepoint s2;
SQL> insert into student values(2, ‘b’, 200);
SQL> savepoint s3;
SQL> insert into student values(3, ‘c’, 300);
SQL> savepoint s4;
SQL> insert into student values(4, ‘d’, 400);
Before rollback
NO NAME MARKS
--- ------- ----------
1 a 100
2 b 200
3 c 300
4 d 400

SQL> rollback to savepoint s3;
Or
SQL> rollback to s3;
This will rollback last two records.
NO NAME MARKS
--- ------- ----------
1 a 100
2 b 200

USING DCL
DCL commands are used to granting and
revoking the permissions.
USING GRANT
This is used to grant the privileges to other
users.
Syntax:
Grant <privileges> on <object_name> to
<user_name> [with grant option];
Ex:
SQL> grant select on student to sudha; --
you can give individual privilege
SQL> grant select, insert on student to
sudha; -- you can give set of privileges
SQL> grant all on student to sudha; --

you can give all privileges
The sudha user has to use dot method to
access the object.
SQL> select * from saketh.student;
The sudha user can not grant permission on
student table to other users. To get this
type of option use the following.
SQL> grant all on student to sudha with
grant option;
Now sudha user also grant permissions on
student table.
USING REVOKE
This is used to revoke the privileges from the
users to which you granted the privileges.
Syntax:
Revoke <privileges> on <object_name>
from <user_name>;
Ex:

SQL> revoke select on student form sudha;
-- you can revoke individual privilege
SQL> revoke select, insert on student from
sudha; -- you can revoke set of privileges
SQL> revoke all on student from sudha; --
you can revoke all privileges
USING ALIASES
CREATE WITH SELECT
We can create a table using existing table
[along with data].
Syntax:
Create table <new_table_name> [col1, col2,
col3 ... coln] as select * from
<old_table_name>;
Ex:
SQL> create table student1 as select * from
student;

Creating table with your own column names.
SQL> create table student2(sno, sname,
smarks) as select * from student;
Creating table with specified columns.
SQL> create table student3 as select
no,name from student;
Creating table with out table data.
SQL> create table student2(sno, sname,
smarks) as select * from student where 1 = 2;
In the above where clause give any condition
which does not satisfy.
INSERT WITH SELECT
Using this we can insert existing table data to a
another table in a single trip. But the table
structure should be same.
Syntax:
Insert into <table1> select * from
<table2>;

Ex:
SQL> insert into student1 select * from
student;
Inserting data into specified columns
SQL> insert into student1(no, name) select
no, name from student;
COLUMN ALIASES
Syntax:
Select <orginal_col> <alias_name> from
<table_name>;
Ex:
SQL> select no sno from student;
or
SQL> select no “sno” from student;
TABLE ALIASES
If you are using table aliases you can use dot
method to the columns.

Syntax:
Select <alias_name>.<col1>,
<alias_name>.<col2> … <alias_name>.<coln>
from
<table_name> <alias_name>;
Ex:
SQL> select s.no, s.name from student s;
USING MERGE

MERGE
You can use merge command to perform insert
and update in a single command.
Ex:
SQL> Merge into student1 s1
Using (select *From student2) s2
On(s1.no=s2.no)
When matched then
Update set marks = s2.marks
When not matched then
Insert (s1.no,s1.name,s1.marks)
Values(s2.no,s2.name,s2.marks);
In the above the two tables are with the same
structure but we can merge different
structured tables also but the datatype of the
columns should match.
Assume that student1 has columns like
no,name,marks and student2 has columns like
no,
name, hno, city.

SQL> Merge into student1 s1
Using (select *From student2) s2
On(s1.no=s2.no)
When matched then
Update set marks = s2.hno
When not matched then
Insert (s1.no,s1.name,s1.marks)
Values(s2.no,s2.name,s2.hno);
MULTIPLE INSERTS
We have table called DEPT with the following
columns and data
DEPTNO DNAME LOC
-------- -------- ----
10 accounting new york
20 research dallas
30 sales Chicago
40 operations boston

a) CREATE STUDENT TABLE
SQL> Create table student(no
number(2),name varchar(2),marks
number(3));
b) MULTI INSERT WITH ALL FIELDS
SQL> Insert all
Into student values(1,’a’,100)
Into student values(2,’b’,200)
Into student values(3,’c’,300)
Select *from dept where deptno=10;
-- This inserts 3 rows
c) MULTI INSERT WITH SPECIFIED FIELDS
SQL> insert all
Into student (no,name) values(4,’d’)
Intostudent(name,marks)values(’e’,400)

d) MULTI INSERT WITH DUPLICATE ROWS
SQL> insert all
Into student values(1,’a’,100)
Into student values(2,’b’,200)
Select *from dept where deptno > 10;
-- This inserts 9 rows because in the select
statement retrieves 3 records (3 inserts for
each row retrieved)
e) MULTI INSERT WITH CONDITIONS BASED
SQL> Insert all
When deptno > 10 then
Into student1 values(1,’a’,100)
When dname = ‘SALES’ then
Into student2 values(2,’b’,200)
When loc = ‘NEW YORK’ then
Into student3 values(3,’c’,300)

Select *from dept where deptno>10;
-- This inserts 4 rows because the first
condition satisfied 3 times, second condition
satisfied once and the last none.
f) MULTI INSERT WITH CONDITIONS BASED
AND ELSE
SQL> Insert all
When deptno > 100 then
When dname = ‘S’ then
Else
Into student values(4,’d’,400)
Select *from dept where deptno>10;
-- This inserts 3 records because the else
satisfied 3 times
g) MULTI INSERT WITH CONDITIONS BASED

AND FIRST
SQL> Insert first
When deptno = 20 then
When dname = ‘RESEARCH’ then
-- This inserts 1 record because the first
clause avoid to check the remaining
conditions once the condition is satisfied.
h) MULTI INSERT WITH CONDITIONS BASED,
FIRST AND ELSE
SQL> Insert first
When deptno = 30 then
When dname = ‘R’ then

Else
Into student values(4,’d’,400)
-- This inserts 1 record because the else
clause satisfied once
i) MULTI INSERT WITH MULTIBLE TABLES
SQL> Insert all
** You can use multi tables with specified
fields, with duplicate rows, with conditions,

with first and else clauses.
FUNCTIONS
Functions can be categorized as follows.
1 Single row functions
1 Group functions
SINGLE ROW FUNCTIONS
Single row functions can be categorized into

five. These will be applied for each row and
produces individual output for each row.
1 Numeric functions
1 String functions
1 Date functions
1 Miscellaneous functions
1 Conversion functions
NUMERIC FUNCTIONS
1 Abs
1 Sign
1 Sqrt
1 Mod
1 Nvl
1 Power
1 Exp
1 Ln
1 Log
1 Ceil
1 Floor
1 Round
1 Trunk

1 Bitand
1 Greatest
1 Least
1 Coalesce
a) ABS
Absolute value is the measure of the
magnitude of value.
Absolute value is always a positive number.
Syntax: abs (value)
Ex:
SQL> select abs(5), abs(-5), abs(0),
abs(null) from dual;
ABS(5) ABS(-5) ABS(0)
ABS(NULL)
---------- ---------- ----------
-------------
5 5 0
b) SIGN

Sign gives the sign of a value.
Syntax: sign (value)
Ex:
SQL> select sign(5), sign(-5), sign(0),
sign(null) from dual;
SIGN(5) SIGN(-5) SIGN(0)
SIGN(NULL)
---------- ---------- ----------
--------------
1 -1 0
c) SQRT
This will give the square root of the given
value.
Syntax: sqrt (value) -- here value must be
positive.
Ex:
SQL> select sqrt(4), sqrt(0), sqrt(null),

sqrt(1) from dual;
SQRT(4) SQRT(0) SQRT(NULL)
SQRT(1)
---------- ---------- ---------------
----------
2 0 1
d) MOD
This will give the remainder.
Syntax: mod (value, divisor)
Ex:
SQL> select mod(7,4), mod(1,5),
mod(null,null), mod(0,0), mod(-7,4) from dual;
MOD(7,4) MOD(1,5) MOD(NULL,NULL)
MOD(0,0) MOD(-7,4)
------------ ---------- ---------------------
----------- -------------
3 1
0 -3

e) NVL
This will substitutes the specified value in
the place of null values.
Syntax: nvl (null_col, replacement_value)
Ex:
SQL> select * from student; -- here for
3rd
row marks value is null
NO NAME MARKS
--- ------- ---------
1 a 100
2 b 200
3 c
SQL> select no, name, nvl(marks,300) from
student;
NO NAME NVL(MARKS,300)
--- ------- ---------------------
1 a 100
2 b 200

3 c 300
SQL> select nvl(1,2), nvl(2,3), nvl(4,3),
nvl(5,4) from dual;
NVL(1,2) NVL(2,3) NVL(4,3)
NVL(5,4)
---------- ---------- ----------
----------
1 2 4 5
SQL> select nvl(0,0), nvl(1,1),
nvl(null,null), nvl(4,4) from dual;
NVL(0,0) NVL(1,1) NVL(null,null)
NVL(4,4)
---------- ---------- -----------------
----------
0 1 4
f) POWER
Power is the ability to raise a value to a
given exponent.

Syntax: power (value, exponent)
Ex:
SQL> select power(2,5), power(0,0),
power(1,1), power(null,null), power(2,-5)
from dual;
POWER(2,5) POWER(0,0) POWER(1,1)
POWER(NULL,NULL) POWER(2,-5)
-------------- -------------- ----- ---------
----------------------- ---------------
32 1 1
.03125
g) EXP
This will raise e value to the give power.
Syntax: exp (value)
Ex:
SQL> select exp(1), exp(2), exp(0),
exp(null), exp(-2) from dual;

EXP(1) EXP(2) EXP(0)
EXP(NULL) EXP(-2)
-------- --------- --------
------------- ----------
2.71828183 7.3890561 1
.135335283
h) LN
This is based on natural or base e logarithm.
Syntax: ln (value) -- here value must be
greater than zero which is positive only.
Ex:
SQL> select ln(1), ln(2), ln(null) from
dual;
LN(1) LN(2) LN(NULL)
------- ------- ------------
0 .693147181
Ln and Exp are reciprocal to each other.
EXP (3) = 20.0855369

LN (20.0855369) = 3
i) LOG
This is based on 10 based logarithm.
Syntax: log (10, value) -- here value must
be greater than zero which is positive only.
Ex:
SQL> select log(10,100), log(10,2),
log(10,1), log(10,null) from dual;
LOG(10,100) LOG(10,2) LOG(10,1)
LOG(10,NULL)
--------------- ----------- ------------
-----------------
2 .301029996 0
LN (value) = LOG (EXP(1), value)
SQL> select ln(3), log(exp(1),3) from
dual;

LN(3) LOG(EXP(1),3)
------- -----------------
1.09861229 1.09861229
j) CEIL
This will produce a whole number that is
greater than or equal to the specified value.
Syntax: ceil (value)
Ex:
SQL> select ceil(5), ceil(5.1), ceil(-5),
ceil( -5.1), ceil(0), ceil(null) from dual;
CEIL(5) CEIL(5.1) CEIL(-5) CEIL(-
5.1) CEIL(0) CEIL(NULL)
--------- ----------- ----------
------------ -------- --------------
5 6 -5 -5
0
k) FLOOR
This will produce a whole number that is

less than or equal to the specified value.
Syntax: floor (value)
Ex:
SQL> select floor(5), floor(5.1), floor(-
5), floor( -5.1), floor(0), floor(null) from
dual;
FLOOR(5) FLOOR(5.1) FLOOR(-5)
FLOOR(-5.1) FLOOR(0) FLOOR(NULL)
----------- ------------- ------------
-------------- ----------- ----------------
5 5 -5
-6 0
l) ROUND
This will rounds numbers to a given number
of digits of precision.
Syntax: round (value, precision)
Ex:
SQL> select round(123.2345),

round(123.2345,2), round(123.2354,2) from
dual;
ROUND(123.2345) ROUND(123.2345,0)
ROUND(123.2345,2) ROUND(123.2354,2)
--------------------- ------------------------
----------------------- -----------------------
123 123
123.23 123.24
SQL> select round(123.2345,-1),
round(123.2345,-2), round(123.2345,-3),
round(123.2345,-4) from dual;
ROUND(123.2345,-1) ROUND(123.2345,-2)
ROUND(123.2345,-3) ROUND(123.2345,-4)
------------------------ -------------------------
------------------------ ------------------------
120 100
0 0
SQL> select round(123,0), round(123,1),
round(123,2) from dual;

ROUND(123,0) ROUND(123,1)
ROUND(123,2)
----------------- -----------------
----------------
123 123 123
SQL> select round(-123,0), round(-123,1),
round(-123,2) from dual;
ROUND(-123,0) ROUND(-123,1)
ROUND(-123,2)
------------------ -----------------
-------------------
-123 -123
-123
SQL> select round(123,-1), round(123,-2),
round(123,-3), round(-123,-1), round(
-123,-2), round(-123,-3) from dual;
ROUND(123,-1) ROUND(123,-2)
ROUND(123,-3) ROUND(-123,-1) ROUND(-

123,-2)
ROUND(-123,-3)
------------- ------------- -------------
-------------- -------------- --------------------------
120 100 0
-120 -100 0
SQL> select round(null,null), round(0,0),
round(1,1), round(-1,-1), round(-2,-2)
from dual;
ROUND(NULL,NULL) ROUND(0,0)
ROUND(1,1) ROUND(-1,-1) ROUND(-2,-2)
----------------------- --------------
-------------- ---------------- ----------------
0
1 0 0
m) TRUNC
This will truncates or chops off digits of
precision from a number.

Syntax: trunc (value, precision)
Ex:
SQL> select trunc(123.2345),
trunc(123.2345,2), trunc(123.2354,2) from
dual;
TRUNC(123.2345) TRUNC(123.2345,2)
TRUNC(123.2354,2)
--------------------- -----------------------
-----------------------
123 123.23
123.23
SQL> select trunc(123.2345,-1),
trunc(123.2345,-2), trunc(123.2345,-3),
trunc(123.2345,-4) from dual;
TRUNC(123.2345,-1) TRUNC(123.2345,-2)
TRUNC(123.2345,-3) TRUNC(123.2345,-4)
------------------------ ------------------------
----------------------- ------------------------
120 100

0 0
SQL> select trunc(123,0), trunc(123,1),
trunc(123,2) from dual;
TRUNC(123,0) TRUNC(123,1)
TRUNC(123,2)
---------------- ----------------
-----------------
123 123 123
SQL> select trunc(-123,0), trunc(-123,1),
trunc(-123,2) from dual;
TRUNC(-123,0) TRUNC(-123,1)
TRUNC(-123,2)
----------------- -----------------
-----------------
-123 -123
-123
SQL> select trunc(123,-1), trunc(123,-2),
trunc(123,-3), trunc(-123,-1), trunc(

-123,2), trunc(-123,-3) from dual;
TRUNC(123,-1) TRUNC(123,-2) TRUNC(123,-3)
TRUNC(-123,-1) TRUNC(-123,2) TRUNC(-
123,-3)
------------- ------------- ------------- --------------
------------- ---------------------------------
120 100 0
-120 -123 0
SQL> select trunc(null,null), trunc(0,0),
trunc(1,1), trunc(-1,-1), trunc(-2,-2) from
dual;
TRUNC(NULL,NULL) TRUNC(0,0)
TRUNC(1,1) TRUNC(-1,-1) TRUNC(-2,-2)
----------------------- -------------
------------- --------------- ----------------
0
1 0 0
n) BITAND

This will perform bitwise and operation.
Syntax: bitand (value1, value2)
Ex:
SQL> select bitand(2,3), bitand(0,0),
bitand(1,1), bitand(null,null), bitand(-2,-3)
from dual;
BITAND(2,3) BITAND(0,0)
BITAND(1,1) BITAND(NULL,NULL)
BITAND(-2,-3)
-------------- --------------- --------------
------------------------ -----------------
2 0 1
-4
o) GREATEST
This will give the greatest number.
Syntax: greatest (value1, value2, value3 …
valuen)
Ex:

SQL> select greatest(1, 2, 3), greatest(-
1, -2, -3) from dual;
GREATEST(1,2,3) GREATEST(-1,-2,-
3)
--------------------
-----------------------
3 -1
1 If all the values are zeros then it will
display zero.
1 If all the parameters are nulls then it will
display nothing.
1 If any of the parameters is null it will
display nothing.
p) LEAST
This will give the least number.
Syntax: least (value1, value2, value3 …
valuen)
Ex:

SQL> select least(1, 2, 3), least(-1, -2,
-3) from dual;
LEAST(1,2,3) LEAST(-1,-2,-3)
--------------------
-----------------------
1 -3
4 If all the values are zeros then it will
display zero.
display nothing.
display nothing.
q) COALESCE
This will return first non-null value.
Syntax: coalesce (value1, value2, value3 …
valuen)
Ex:
SQL> select coalesce(1,2,3),
coalesce(null,2,null,5) from dual;

COALESCE(1,2,3)
COALESCE(NULL,2,NULL,5)
-------------------
-------------------------------
1 2
STRING FUNCTIONS
18 Initcap
18 Upper
18 Lower
18 Length
18 Rpad
18 Lpad
18 Ltrim
18 Rtrim
18 Trim
18 Translate
18 Replace
18 Soundex
18 Concat ( ‘ || ‘ Concatenation
operator)

18 Ascii
18 Chr
18 Substr
18 Instr
18 Decode
18 Greatest
18 Least
18 Coalesce
a) INITCAP
This will capitalize the initial letter of the
string.
Syntax: initcap (string)
Ex:
SQL> select initcap('computer') from
dual;
INITCAP
-----------
Computer
b) UPPER

This will convert the string into uppercase.
Syntax: upper (string)
Ex:
SQL> select upper('computer') from
dual;
UPPER
-----------
COMPUTER
c) LOWER
This will convert the string into lowercase.
Syntax: lower (string)
Ex:
SQL> select lower('COMPUTER') from
dual;
LOWER

-----------
computer
d) LENGTH
This will give length of the string.
Syntax: length (string)
Ex:
SQL> select length('computer') from
dual;
LENGTH
-----------
8
e) RPAD
This will allows you to pad the right side of a
column with any set of characters.
Syntax: rpad (string, length [,
padding_char])

Ex:
SQL> select rpad('computer',15,'*'),
rpad('computer',15,'*#') from dual;
RPAD('COMPUTER'
RPAD('COMPUTER'
----------------------
----------------------
computer*******
computer*#*#*#*
-- Default padding character was blank
space.
f) LPAD
This will allows you to pad the left side of a
column with any set of characters.
Syntax: lpad (string, length [,
padding_char])
Ex:
SQL> select lpad('computer',15,'*'),
lpad('computer',15,'*#') from dual;

LPAD('COMPUTER'
LPAD('COMPUTER'
---------------------
---------------------
*******computer
*#*#*#*computer
-- Default padding character was blank
space.
g) LTRIM
This will trim off unwanted characters from
the left end of string.
Syntax: ltrim (string [,unwanted_chars])
Ex:
SQL> select ltrim('computer','co'),
ltrim('computer','com') from dual;
LTRIM( LTRIM
-------- ---------

mputer puter
SQL> select ltrim('computer','puter'),
ltrim('computer','omputer') from dual;
LTRIM('C LTRIM('C
---------- ----------
computer computer
-- If you haven’t specify any unwanted
characters it will display entire string.
h) RTRIM
the right end of string.
Syntax: rtrim (string, [ unwanted_chars])
Ex:
SQL> select rtrim('computer','er'),
rtrim('computer','ter') from dual;
RTRIM( RTRIM
-------- ---------
comput compu

SQL> select rtrim('computer','comput’),
rtrim('computer','compute') from dual;
RTRIM('C RTRIM('C
---------- ----------
computer computer
-- If you haven’t specify any unwanted
characters it will display entire string.
i) TRIM
the both sides of string.
Syntax: trim (unwanted_chars from string)
Ex:
SQL> select trim( 'i' from 'indiani') from
dual;
TRIM(
-----
ndian

SQL> select trim( leading'i' from 'indiani')
from dual; -- this will work as LTRIM
TRIM(L
------
ndiani
SQL> select trim( trailing'i' from 'indiani')
from dual; -- this will work as RTRIM
TRIM(T
------
Indian
j) TRANSLATE
This will replace the set of characters,
character by character.
Syntax: translate (string, old_chars,
new_chars)

Ex:
SQL> select translate('india','in','xy')
from dual;
TRANS
--------
xydxa
k) REPLACE
This will replace the set of characters, string
by string.
Syntax: replace (string, old_chars [,
new_chars])
Ex:
SQL> select replace('india','in','xy'),
replace(‘india’,’in’) from dual;
REPLACE REPLACE
----------- -----------
Xydia dia

l) SOUNDEX
This will be used to find words that sound
like other words, exclusively used in where
clause.
Syntax: soundex (string)
Ex:
SQL> select * from emp where
soundex(ename) = soundex('SMIT');
EMPNO ENAME JOB MGR
HIREDATE SAL DEPTNO
-------- -------- ----- -----
------------ --------- ----------
7369 SMITH CLERK 7902 17-
DEC-80 500 20
m) CONCAT
This will be used to combine two strings
only.
Syntax: concat (string1, string2)

Ex:
SQL> select concat('computer','
operator') from dual;
CONCAT('COMPUTER'
-------------------------
computer operator
If you want to combine more than two
strings you have to use concatenation
operator(||).
SQL> select 'how' || ' are' || ' you' from
dual;
'HOW'||'ARE
---------------
how are you
n) ASCII
This will return the decimal representation in
the database character set of the first

character of the string.
Syntax: ascii (string)
Ex:
SQL> select ascii('a'), ascii('apple') from
dual;
ASCII('A') ASCII('APPLE')
------------ ------------------
97 97
o) CHR
This will return the character having the
binary equivalent to the string in either the
database character set or the national
character set.
Syntax: chr (number)
Ex:
SQL> select chr(97) from dual;

CHR
-----
a
p) SUBSTR
This will be used to extract substrings.
Syntax: substr (string, start_chr_count [,
no_of_chars])
Ex:
SQL> select substr('computer',2),
substr('computer',2,5), substr('computer',3,7)
from dual;
SUBSTR( SUBST SUBSTR
---------- ------- --------
omputer omput mputer
1 If no_of_chars parameter is negative
then it will display nothing.
1 If both parameters except string are
null or zeros then it will display

nothing.
1 If no_of_chars parameter is greater
than the length of the string then it
ignores and calculates based on the
orginal string length.
1 If start_chr_count is negative then it
will extract the substring from right
end.
1 2 3 4 5 6 7 8
C O M P U T E R
-8 -7 -6 -5 -4 -3 -2
-1
q) INSTR
This will allows you for searching through a
string for set of characters.
Syntax: instr (string, search_str [,
start_chr_count [, occurrence] ])
Ex:
SQL> select instr('information','o',4,1),

instr('information','o',4,2) from dual;
INSTR('INFORMATION','O',4,1)
INSTR('INFORMATION','O',4,2)
------------------------------------
-------------------------------------
4
10
1 If you are not specifying start_chr_count
and occurrence then it will start
search from the beginning and finds first
occurrence only.
2 If both parameters start_chr_count and
occurrence are null, it will display
nothing.
r) DECODE
Decode will act as value by value
substitution.
For every value of field, it will checks for a
match in a series of if/then tests.

Syntax: decode (value, if1, then1, if2, then2,
……. else);
Ex:
SQL> select sal,
decode(sal,500,'Low',5000,'High','Medium')
from emp;
SAL DECODE
----- ---------
500 Low
2500 Medium
2000 Medium
3500 Medium
3000 Medium
5000 High
4000 Medium
5000 High
1800 Medium
1200 Medium
2000 Medium
2700 Medium

2200 Medium
3200 Medium
SQL> select decode(1,1,3),
decode(1,2,3,4,4,6) from dual;
DECODE(1,1,3)
DECODE(1,2,3,4,4,6)
-----------------
------------------------
3 6
1 If the number of parameters are odd and
different then decode will display
nothing.
2 If the number of parameters are even
and different then decode will display
last
value.
3 If all the parameters are null then decode
will display nothing.
3 If all the parameters are zeros then
decode will display zero.
s) GREATEST

This will give the greatest string.
Syntax: greatest (strng1, string2, string3 …
stringn)
Ex:
SQL> select greatest('a', 'b', 'c'),
greatest('satish','srinu','saketh') from dual;
GREAT GREAT
------- -------
c srinu
display nothing.
display nothing.
t) LEAST
This will give the least string.
Syntax: greatest (strng1, string2, string3 …

stringn)
Ex:
SQL> select least('a', 'b', 'c'),
least('satish','srinu','saketh') from dual;
LEAST LEAST
------- -------
a saketh
display nothing.
display nothing.
u) COALESCE
This will gives the first non-null string.
Syntax: coalesce (strng1, string2, string3 …
stringn)
Ex:

SQL> select coalesce('a','b','c'),
coalesce(null,'a',null,'b') from dual;
COALESCE COALESCE
----------- -----------
a a
DATE FUNCTIONS
39 Sysdate
39 Current_date
39 Current_timestamp
39 Systimestamp
39 Localtimestamp
39 Dbtimezone
39 Sessiontimezone
39 To_char
39 To_date
39 Add_months
39 Months_between
39 Next_day
39 Last_day
39 Extract

39 Greatest
39 Least
39 Round
39 Trunc
39 New_time
39 Coalesce
Oracle default date format is DD-MON-YY.
We can change the default format to our
desired format by using the following
command.
SQL> alter session set nls_date_format = ‘DD-
MONTH-YYYY’;
But this will expire once the session was
closed.
a) SYSDATE
This will give the current date and time.
Ex:
SQL> select sysdate from dual;
SYSDATE

-----------
24-DEC-06
b) CURRENT_DATE
This will returns the current date in the
session’s timezone.
Ex:
SQL> select current_date from dual;
CURRENT_DATE
------------------
24-DEC-06
c) CURRENT_TIMESTAMP
This will returns the current timestamp with
the active time zone information.
Ex:
SQL> select current_timestamp from
dual;

CURRENT_TIMESTAMP
----------------------------------------------
-----------------------------
24-DEC-06 03.42.41.383369 AM
+05:30
d) SYSTIMESTAMP
This will returns the system date, including
fractional seconds and time zone of the
database.
Ex:
SQL> select systimestamp from dual;
SYSTIMESTAMP
----------------------------------------------
-----------------------------
24-DEC-06 03.49.31.830099 AM
+05:30
e) LOCALTIMESTAMP
This will returns local timestamp in the

active time zone information, with no time
zone information shown.
Ex:
SQL> select localtimestamp from dual;
LOCALTIMESTAMP
----------------------------------------------
-----------------------------
24-DEC-06 03.44.18.502874 AM
f) DBTIMEZONE
This will returns the current database time
zone in UTC format. (Coordinated Universal
Time)
Ex:
SQL> select dbtimezone from dual;
DBTIMEZONE
---------------
-07:00
g) SESSIONTIMEZONE
This will returns the value of the current
session’s time zone.

Ex:
SQL> select sessiontimezone from dual;
SESSIONTIMEZONE
------------------------------------
+05:30
h) TO_CHAR
This will be used to extract various date
formats.
The available date formats as follows.
Syntax: to_char (date, format)
DATE FORMATS
D -- No of days in week
DD -- No of days in month
DDD -- No of days in year
MM -- No of month
MON -- Three letter abbreviation of

month
MONTH -- Fully spelled out month
RM -- Roman numeral month
DY -- Three letter abbreviated day
DAY -- Fully spelled out day
Y -- Last one digit of the year
YY -- Last two digits of the year
YYY -- Last three digits of the year
YYYY -- Full four digit year
SYYYY -- Signed year
I -- One digit year from ISO
standard
IY -- Two digit year from ISO
standard
IYY -- Three digit year from ISO
standard
IYYY -- Four digit year from ISO
standard
Y, YYY -- Year with comma
YEAR -- Fully spelled out year
CC -- Century
Q -- No of quarters

W -- No of weeks in month
WW -- No of weeks in year
IW -- No of weeks in year from ISO
standard
HH -- Hours
MI -- Minutes
SS -- Seconds
FF -- Fractional seconds
AM or PM -- Displays AM or PM
depending upon time of day
A.M or P.M -- Displays A.M or P.M
depending upon time of day
AD or BC -- Displays AD or BC
depending upon the date
A.D or B.C -- Displays AD or BC
depending upon the date
FM -- Prefix to month or day,
suppresses padding of month or day
TH -- Suffix to a number
SP -- suffix to a number to be spelled
out
SPTH -- Suffix combination of TH

and SP to be both spelled out
THSP -- same as SPTH
Ex:
SQL> select to_char(sysdate,'dd month yyyy
hh:mi:ss am dy') from dual;
TO_CHAR(SYSDATE,'DD MONTH
YYYYHH:MI
----------------------------------------------
------
24 december 2006 02:03:23 pm sun
SQL> select to_char(sysdate,'dd month
year') from dual;
TO_CHAR(SYSDATE,'DDMONTHYEAR')
----------------------------------------------
---------
24 december two thousand six
SQL> select to_char(sysdate,'dd fmmonth

year') from dual;
TO_CHAR(SYSDATE,'DD FMMONTH
YEAR')
----------------------------------------------
---------
24 december two thousand six
SQL> select to_char(sysdate,'ddth DDTH')
from dual;
TO_CHAR(S
------------
24th 24TH
SQL> select to_char(sysdate,'ddspth
DDSPTH') from dual;
TO_CHAR(SYSDATE,'DDSPTHDDSPTH
------------------------------------------
twenty-fourth TWENTY-FOURTH
SQL> select to_char(sysdate,'ddsp Ddsp
DDSP ') from dual;

TO_CHAR(SYSDATE,'DDSPDDSPDDSP')
----------------------------------------------
--
twenty-four Twenty-Four TWENTY-
FOUR
i) TO_DATE
This will be used to convert the string into
data format.
Syntax: to_date (date)
Ex:
SQL> select
to_char(to_date('24/dec/2006','dd/mon/yyyy'
), 'dd * month * day')
from dual;
TO_CHAR(TO_DATE('24/DEC/20
--------------------------
24 * december * Sunday

-- If you are not using to_char oracle will
display output in default date format.
j) ADD_MONTHS
This will add the specified months to the
given date.
Syntax: add_months (date, no_of_months)
Ex:
SQL> select add_months(to_date('11-
jan-1990','dd-mon-yyyy'), 5) from dual;
ADD_MONTHS
----------------
11-JUN-90
SQL> select add_months(to_date('11-jan-
1990','dd-mon-yyyy'), -5) from dual;
ADD_MONTH
---------------
11-AUG-89

1 If no_of_months is zero then it will
display the same date.
1 If no_of_months is null then it will
display nothing.
k) MONTHS_BETWEEN
This will give difference of months between
two dates.
Syntax: months_between (date1, date2)
Ex:
SQL> select
months_between(to_date('11-aug-1990','dd-
mon-yyyy'), to_date('11-
jan-1990','dd-mon-yyyy')) from dual;
MONTHS_BETWEEN(TO_DATE('11-AUG-
1990','DD-MON-YYYY'),TO_DATE('11-JAN-
1990','DD-MON-YYYY'))

---------------------------------------------------
--------------------------------------------
7
SQL> select
months_between(to_date('11-jan-1990','dd-
mon-yyyy'), to_date('11-
aug-1990','dd-mon-yyyy')) from
dual;
MONTHS_BETWEEN(TO_DATE('11-JAN-
1990','DD-MON-YYYY'),TO_DATE('11-AUG-
1990','DD-MON-YYYY'))
---------------------------------------------------
----------------------------------------------
-7
l) NEXT_DAY
This will produce next day of the given day
from the specified date.

Syntax: next_day (date, day)
Ex:
SQL> select next_day(to_date('24-dec-
2006','dd-mon-yyyy'),'sun') from dual;
NEXT_DAY(
-------------
31-DEC-06
-- If the day parameter is null then it will
display nothing.
m) LAST_DAY
This will produce last day of the given date.
Syntax: last_day (date)
Ex:
SQL> select last_day(to_date('24-dec-
2006','dd-mon-yyyy'),'sun') from dual;
LAST_DAY(
-------------

31-DEC-06
n) EXTRACT
This is used to extract a portion of the date
value.
Syntax: extract ((year | month | day | hour |
minute | second), date)
Ex:
SQL> select extract(year from sysdate)
from dual;
EXTRACT(YEARFROMSYSDATE)
------------------------------------
2006
-- You can extract only one value at a time.
o) GREATEST
This will give the greatest date.
Syntax: greatest (date1, date2, date3 …

daten)
Ex:
SQL> select greatest(to_date('11-jan-
90','dd-mon-yy'),to_date('11-mar-90','dd-
mon-yy'),to_date('11-apr-90','dd-
mon-yy')) from dual;
GREATEST(
-------------
11-APR-90
p) LEAST
This will give the least date.
Syntax: least (date1, date2, date3 … daten)
Ex:
SQL> select least(to_date('11-jan-
90','dd-mon-yy'),to_date('11-mar-90','dd-mon-
yy'),to_date('11-apr-90','dd-mon-
yy')) from dual;
LEAST(

-------------
11-JAN-90
q) ROUND
Round will rounds the date to which it was
equal to or greater than the given date.
Syntax: round (date, (day | month | year))
If the second parameter was year then round
will checks the month of the given date in
the following ranges.
JAN-- JUN
JUL -- DEC
If the month falls between JAN and JUN then
it returns the first day of the current year.
If the month falls between JUL and DEC then
it returns the first day of the next year.
If the second parameter was month then
round will checks the day of the given date in

the following ranges.
1 -- 15
16 -- 31
If the day falls between 1 and 15 then it
returns the first day of the current month.
If the day falls between 16 and 31 then it
returns the first day of the next month.
If the second parameter was day then round
will checks the week day of the given date
in the following ranges.
SUN -- WED
THU -- SUN
If the week day falls between SUN and WED
then it returns the previous sunday.
If the weekday falls between THU and SUN
then it returns the next sunday.
1 If the second parameter was null then it
returns nothing.

1 If the you are not specifying the second
parameter then round will resets the time
to the begining of the current day in case of
user specified date.
parameter then round will resets the time
to the begining of the next day in case of
sysdate.
Ex:
SQL> select round(to_date('24-dec-
04','dd-mon-yy'),'year'), round(to_date('11-
mar-
06','dd-mon-yy'),'year') from dual;
ROUND(TO_ ROUND(TO_
------------ ---------------
01-JAN-05 01-JAN-06
SQL> select round(to_date('11-jan-
04','dd-mon-yy'),'month'), round(to_date('18-
jan-04','dd-mon-yy'),'month') from
dual;

ROUND(TO_ ROUND(TO_
------------- ---------------
01-JAN-04 01-FEB-04
SQL> select round(to_date('26-dec-
06','dd-mon-yy'),'day'), round(to_date('29-
dec-
06','dd-mon-yy'),'day') from dual;
ROUND(TO_ ROUND(TO_
-------------- --------------
24-DEC-06 31-DEC-06
SQL> select to_char(round(to_date('24-
dec-06','dd-mon-yy')), 'dd mon yyyy
hh:mi:ss am') from dual;
TO_CHAR(ROUND(TO_DATE('
---------------------------------
24 dec 2006 12:00:00 am
r) TRUNC
Trunc will chops off the date to which it was

equal to or less than the given date.
Syntax: trunc (date, (day | month | year))
1 If the second parameter was year then it
always returns the first day of the current
year.
1 If the second parameter was month then it
always returns the first day of the current
month.
1 If the second parameter was day then it
always returns the previous sunday.
1 If the second parameter was null then it
returns nothing.
parameter then trunk will resets the time
to the begining of the current day.
Ex:
SQL> select trunc(to_date('24-dec-
04','dd-mon-yy'),'year'), trunc(to_date('11-
mar-
06','dd-mon-yy'),'year') from dual;

TRUNC(TO_ TRUNC(TO_
------------- --------------
01-JAN-04 01-JAN-06
SQL> select trunc(to_date('11-jan-
04','dd-mon-yy'),'month'), trunc(to_date('18-jan-
04','dd-mon-yy'),'month') from
dual;
TRUNC(TO_ TRUNC(TO_
------------- -------------
01-JAN-04 01-JAN-04
SQL> select trunc(to_date('26-dec-06','dd-
mon-yy'),'day'), trunc(to_date('29-dec-
06','dd-mon-yy'),'day') from dual;
TRUNC(TO_ TRUNC(TO_
------------- --------------
24-DEC-06 24-DEC-06
SQL> select to_char(trunc(to_date('24-
dec-06','dd-mon-yy')), 'dd mon yyyy hh:mi:ss

am') from dual;
TO_CHAR(TRUNC(TO_DATE('
---------------------------------
24 dec 2006 12:00:00 am
s) NEW_TIME
This will give the desired timezone’s date
and time.
Syntax: new_time (date, current_timezone,
desired_timezone)
Available timezones are as follows.
TIMEZONES
AST/ADT -- Atlantic standard/day
light time
BST/BDT -- Bering standard/day
light time
CST/CDT -- Central standard/day
light time

EST/EDT -- Eastern standard/day
light time
GMT -- Greenwich mean time
HST/HDT -- Alaska-Hawaii
standard/day light time
MST/MDT -- Mountain standard/day
light time
NST -- Newfoundland standard
time
PST/PDT -- Pacific standard/day
light time
YST/YDT -- Yukon standard/day
light time
Ex:
SQL> select
to_char(new_time(sysdate,'gmt','yst'),'dd mon
yyyy hh:mi:ss am') from
dual;
TO_CHAR(NEW_TIME(SYSDAT
-----------------------------------
24 dec 2006 02:51:20 pm

SQL> select
to_char(new_time(sysdate,'gmt','est'),'dd mon
yyyy hh:mi:ss am') from
dual;
TO_CHAR(NEW_TIME(SYSDAT
-----------------------
24 dec 2006 06:51:26 pm
t) COALESCE
This will give the first non-null date.
Syntax: coalesce (date1, date2, date3 …
daten)
Ex:
SQL> select coalesce('12-jan-90','13-jan-
99'), coalesce(null,'12-jan-90','23-mar-
98',null) from dual;
COALESCE( COALESCE(
------------- ------------

12-jan-90 12-jan-90
MISCELLANEOUS FUNCTIONS
59 Uid
59 User
59 Vsize
59 Rank
59 Dense_rank
a) UID
This will returns the integer value
corresponding to the user currently logged in.
Ex:
SQL> select uid from dual;
UID
----------
319
b) USER
This will returns the login’s user name.

Ex:
SQL> select user from dual;
USER
----------------
SAKETH
c) VSIZE
This will returns the number of bytes in the
expression.
Ex:
SQL> select vsize(123),
vsize('computer'), vsize('12-jan-90') from
dual;
VSIZE(123) VSIZE('COMPUTER')
VSIZE('12-JAN-90')
------------- -----------------------
----------------------
3 8
9

d) RANK
This will give the non-sequential ranking.
Ex:
SQL> select rownum,sal from (select sal
from emp order by sal desc);
ROWNUM SAL
---------- ----------
1 5000
2 3000
3 3000
4 2975
5 2850
6 2450
7 1600
8 1500
9 1300
10 1250
11 1250
12 1100
13 1000
14 950

15 800
SQL> select rank(2975) within group(order
by sal desc) from emp;
RANK(2975)WITHINGROUP(ORDERBYS
ALDESC)
----------------------------------------------
-----------
4
d) DENSE_RANK
This will give the sequential ranking.
Ex:
SQL> select dense_rank(2975) within
group(order by sal desc) from emp;
DENSE_RANK(2975)WITHINGROUP(OR
DERBYSALDESC)
----------------------------------------------
-------------------
3

CONVERSION FUNCTIONS
64 Bin_to_num
64 Chartorowid
64 Rowidtochar
64 To_number
64 To_char
64 To_date
a) BIN_TO_NUM
This will convert the binary value to its
numerical equivalent.
Syntax: bin_to_num( binary_bits)
Ex:
SQL> select bin_to_num(1,1,0) from
dual;
BIN_TO_NUM(1,1,0)
------------------------
6

1 If all the bits are zero then it produces
zero.
1 If all the bits are null then it produces an
error.
b) CHARTOROWID
This will convert a character string to act
like an internal oracle row identifier or rowid.
c) ROWIDTOCHAR
This will convert an internal oracle row
identifier or rowid to character string.
d) TO_NUMBER
This will convert a char or varchar to
number.
e) TO_CHAR
This will convert a number or date to
character string.

f) TO_DATE
This will convert a number, char or varchar
to a date.
GROUP FUNCTIONS
70 Sum
70 Avg
70 Max
70 Min
70 Count
Group functions will be applied on all the rows
but produces single output.
a) SUM
This will give the sum of the values of the
specified column.
Syntax: sum (column)

Ex:
SQL> select sum(sal) from emp;
SUM(SAL)
----------
38600
b) AVG
This will give the average of the values of
the specified column.
Syntax: avg (column)
Ex:
SQL> select avg(sal) from emp;
AVG(SAL)
---------------
2757.14286
c) MAX
This will give the maximum of the values of

Syntax: max (column)
Ex:
SQL> select max(sal) from emp;
MAX(SAL)
----------
5000
d) MIN
This will give the minimum of the values of
Syntax: min (column)
Ex:
SQL> select min(sal) from emp;
MIN(SAL)
----------
500

e) COUNT
This will give the count of the values of the
specified column.
Syntax: count (column)
Ex:
SQL> select count(sal),count(*) from
emp;
COUNT(SAL) COUNT(*)
-------------- ------------
14 14

CONSTRAINTS
Constraints are categorized as follows.
Domain integrity constraints
1 Not null
1 Check
Entity integrity constraints
1 Unique
1 Primary key
Referential integrity constraints
1 Foreign key
Constraints are always attached to a column
not a table.
We can add constraints in three ways.
2 Column level -- along with the
column definition

2 Table level -- after the table
definition
2 Alter level -- using alter command
While adding constraints you need not specify
the name but the type only, oracle will
internally name the constraint.
If you want to give a name to the constraint,
you have to use the constraint clause.
NOT NULL
This is used to avoid null values.
We can add this constraint in column level only.
Ex:
SQL> create table student(no number(2)
not null, name varchar(10), marks
number(3));
constraint nn not null, name varchar(10),
marks number(3));

CHECK
This is used to insert the values based on
specified condition.
We can add this constraint in all three levels.
Ex:
COLUMN LEVEL
SQL> create table student(no number(2) ,
name varchar(10), marks number(3) check
(marks > 300));
name varchar(10), marks number(3)
constraint ch check(marks > 300));
TABLE LEVEL
name varchar(10), marks number(3), check
(marks > 300));
name varchar(10), marks number(3),
constraint ch check(marks > 300));

ALTER LEVEL
SQL> alter table student add
check(marks>300);
SQL> alter table student add constraint ch
check(marks>300);
UNIQUE
This is used to avoid duplicates but it allow
nulls.
We can add this constraint in all three levels.
Ex:
COLUMN LEVEL
unique, name varchar(10), marks
number(3));

constraint un unique, name varchar(10),
marks number(3));
TABLE LEVEL
unique(no));
constraint un unique(no));
ALTER LEVEL
SQL> alter table student add unique(no);
SQL> alter table student add constraint un
unique(no);
PRIMARY KEY
1 This is used to avoid duplicates and nulls.
This will work as combination of unique
and not null.

1 Primary key always attached to the parent
table.
1 We can add this constraint in all three
levels.
Ex:
COLUMN LEVEL
primary key, name varchar(10), marks
number(3));
constraint pk primary key, name varchar(10),
marks number(3));
TABLE LEVEL
primary key(no));

constraint pk primary key(no));
ALTER LEVEL
SQL> alter table student add primary
key(no);
SQL> alter table student add constraint pk
primary key(no);
FOREIGN KEY
1 This is used to reference the parent table
primary key column which allows
duplicates.
1 Foreign key always attached to the child
table.
1 We can add this constraint in table and
alter levels only.
Ex:
TABLE LEVEL
SQL> create table emp(empno number(2),

ename varchar(10), deptno number(2),
primary key(empno), foreign
key(deptno) references dept(deptno));
constraint pk primary key(empno),
constraint fk foreign key(deptno) references
dept(deptno));
ALTER LEVEL
SQL> alter table emp add foreign
key(deptno) references dept(deptno);
SQL> alter table emp add constraint fk
foreign key(deptno) references dept(deptno);
Once the primary key and foreign key
relationship has been created then you can not
remove any parent record if the dependent
childs exists.
USING ON DELTE CASCADE

By using this clause you can remove the parent
record even it childs exists.
Because when ever you remove parent record
oracle automatically removes all its dependent
records from child table, if this clause is
present while creating foreign key constraint.
Ex:
TABLE LEVEL
primary key(empno), foreign
key(deptno) references dept(deptno) on delete
cascade);
constraint pk primary key(empno),
constraint fk foreign key(deptno) references
dept(deptno) on delete cascade);
ALTER LEVEL

key(deptno) references dept(deptno) on delete
cascade;
foreign key(deptno) references dept(deptno) on
delete cascade;
COMPOSITE KEYS
A composite key can be defined on a
combination of columns.
We can define composite keys on entity
integrity and referential integrity constraints.
Composite key can be defined in table and alter
levels only.
Ex:
UNIQUE (TABLE LEVEL)
unique(no,name));

constraint un unique(no,name));
UNIQUE (ALTER LEVEL)
SQL> alter table student add
unique(no,name);
unique(no,name);
PRIMARY KEY (TABLE LEVEL)
primary key(no,name));
constraint pk primary key(no,name));
PRIMARY KEY (ALTER LEVEL)
SQL> alter table student add primary
key(no,anme);

SQL> alter table student add constraint pk
primary key(no,name);
FOREIGN KEY (TABLE LEVEL)
dname varchar(10), primary
key(empno), foreign key(deptno,dname)
references
dept(deptno,dname));
dname varchar(10), constraint pk
primary key(empno), constraint fk foreign
key(deptno,dname) references
dept(deptno,dname));
FOREIGN KEY (ALTER LEVEL)
key(deptno,dname) references
dept(deptno,dname);

foreign key(deptno,dname) references
dept(deptno,dname);
DEFERRABLE CONSTRAINTS
Each constraint has two additional attributes to
support deferred checking of constraints.
1 Deferred initially immediate
1 Deferred initially deferred
Deferred initially immediate checks for
constraint violation at the time of insert.
Deferred initially deferred checks for constraint
violation at the time of commit.
Ex:
SQL> create table student(no number(2),
constraint un unique(no) deferred
initially immediate);
SQL> create table student(no number(2),
constraint un unique(no) deferred

initially deferred);
unique(no) deferrable initially deferred;
SQL> set constraints all immediate;
This will enable all the constraints violations
at the time of inserting.
SQL> set constraints all deferred;
This will enable all the constraints violations
at the time of commit.
OPERATIONS WITH CONSTRAINTS
Possible operations with constraints as follows.
3 Enable
3 Disable
3 Enforce
3 Drop
ENABLE
This will enable the constraint. Before enable,

the constraint will check the existing data.
Ex:
SQL> alter table student enable constraint
un;
DISABLE
This will disable the constraint.
Ex:
SQL> alter table student enable constraint
un;
ENFORCE
This will enforce the constraint rather than
enable for future inserts or updates.
This will not check for existing data while
enforcing data.
Ex:
SQL> alter table student enforce constraint
un;

DROP
This will remove the constraint.
Ex:
SQL> alter table student drop constraint un;
Once the table is dropped, constraints
automatically will drop.
CASE AND DEFAULT
CASE
Case is similar to decode but easier to

understand while going through coding
Ex:
SQL> Select sal,
Case sal
When 500 then ‘low’
When 5000 then ‘high’
Else ‘medium’
End case
From emp;
SAL CASE
----- --------
500 low
2500 medium
2000 medium
3500 medium
3000 medium
5000 high
4000 medium
5000 high
1800 medium
1200 medium

2000 medium
2700 medium
2200 medium
3200 medium
DEFAULT
Default can be considered as a substitute
behavior of not null constraint when applied to
new rows being entered into the table.
When you define a column with the default
keyword followed by a value, you are actually
telling the database that, on insert if a row was
not assigned a value for this column, use the
default value that you have specified.
Default is applied only during insertion of new
rows.
Ex:
default 11,name varchar(2));
SQL> insert into student values(1,'a');

SQL> insert into student(name) values('b');
NO NAME
------ ---------
1 a
11 b
SQL> insert into student values(null, ‘c’);
NO NAME
------ ---------
1 a
11 b
C
-- Default can not override nulls.
ABSTRACT DATA TYPES

Some times you may want type which holds all
types of data including numbers, chars and
special characters something like this. You can
not achieve this using pre-defined types.
You can define custom types which holds your
desired data.
Ex:
Suppose in a table we have address column
which holds hno and city information.
We will define a custom type which holds
both numeric as well as char data.
CREATING ADT
SQL> create type addr as object(hno
number(3),city varchar(10)); /
CREATING TABLE BASED ON ADT
SQL> create table student(no
number(2),name varchar(2),address addr);

INSERTING DATA INTO ADT TABLES
SQL> insert into student
values(1,'a',addr(111,'hyd'));
values(2,'b',addr(222,'bang'));
values(3,'c',addr(333,'delhi'));
SELECTING DATA FROM ADT TABLES
NO NAME ADDRESS(HNO, CITY)
--- ------- -------------------------
1 a ADDR(111, 'hyd')
2 b ADDR(222, 'bang')
3 c ADDR(333, 'delhi')
SQL> select
no,name,s.address.hno,s.address.city from
student s;

NO NAME ADDRESS.HNO ADDRESS.CITY
---- ------- ----------------- ----------------
1 a 111 hyd
2 b 222 bang
3 c 333 delhi
UPDATE WITH ADT TABLES
SQL> update student s set s.address.city =
'bombay' where s.address.hno = 333;
SQL> select
student s;
---- ------- ----------------- ----------------
1 a 111 hyd
2 b 222 bang
3 c 333 bombay
DELETE WITH ADT TABLES
SQL> delete student s where s.address.hno =

111;
SQL> select
student s;
---- ------- ----------------- ----------------
2 b 222 bang
3 c 333 bombay
DROPPING ADT
SQL> drop type addr;
OBJECT VIEWS AND METHODS
OBJECT VIEWS
If you want to implement objects with the
existing table, object views come into picture.

You define the object and create a view which
relates this object to the existing table nothing
but object view.
Object views are used to relate the user
defined objects to the existing table.
Ex:
1) Assume that the table student has
already been created with the following
columns
SQL/
2) Create the following types
SQL> create type addr as object(hno
number(2),city varchar(10));/
SQL> create type stud as object(name
varchar(10),address addr);/
3) Relate the objects to the student table by
creating the object view
SQL> create view
student_ov(no,stud_info) as select
no,stud(name,addr(hno,city))

from student;
4) Now you can insert data into student
table in two ways
a) By regular insert
SQL> Insert into student
values(1,’sudha’,111,’hyd’);
b) By using object view
SQL> Insert into student_ov
values(1,stud(‘sudha’,addr(111,’hyd’)));
METHODS
You can define methods which are nothing but
functions in types and apply in the tables which
holds the types;
Ex:
1) Defining methods in types
SQL> Create type stud as object(name
varchar(10),marks number(3),
Member function makrs_f(marks in
number) return number,
Pragma

restrict_references(marks_f,wnds,rnds,wnps,fn
ps));/
2) Defining type body
SQL> Create type body stud as
Member function marks_f(marks in
number) return number is
Begin
Return (marks+100);
End marks_f;
End;/
3) Create a table using stud type
number(2),info stud);
4) Insert some data into student table
values(1,stud(‘sudha’,100));
5) Using method in select
SQL> Select
s.info.marks_f(s.info.marks) from student s;
-- Here we are using the pragma
restrict_references to avoid the writes to the
Database.

VARRAYS AND NESTED TABLES
VARRAYS
A varying array allows you to store repeating
attributes of a record in a single row but with
limit.
Ex:
1) We can create varrays using oracle types

as well as user defined types.
a) Varray using pre-defined types
SQL> Create type va as varray(5) of
varchar(10);/
b) Varrays using user defined types
SQL> Create type addr as object(hno
SQL> Create type va as varray(5) of
addr;/
2) Using varray in table
number(2),name varchar(10),address va);
3) Inserting values into varray table
values(1,’sudha’,va(addr(111,’hyd’)));
values(2,’jagan’,va(addr(111,’hyd’),addr(222,’ban
g’)));
4) Selecting data from varray table
SQL> Select * from student;
-- This will display varray column data
along with varray and adt;

SQL> Select no,name, s.* from student
s1, table(s1.address) s;
-- This will display in general format
5) Instead of s.* you can specify the columns
in varray
SQL> Select no,name, s.hno,s.city from
student s1,table(s1.address) s;
-- Update and delete not possible in varrays.
-- Here we used table function which will
take the varray column as input for producing
output excluding varray and types.
NESTED TABLES
A nested table is, as its name implies, a table
within a table. In this case it is a table that is
represented as a column within another table.
Nested table has the same effect of varrays but
has no limit.

Ex:
1) We can create nested tables using oracle
types and user defined types which has no
limit.
a) Nested tables using pre-defined types
SQL> Create type nt as table of
varchar(10);/
b) Nested tables using user defined types
SQL> Create type addr as object(hno
SQL> Create type nt as table of addr;/
2) Using nested table in table
number(2),name varchar(10),address nt)
nested table
address store as student_temp;
3) Inserting values into table which has
nested table
SQL> Insert into student values
(1,’sudha’,nt(addr(111,’hyd’)));
SQL> Insert into student values

(2,’jagan’,nt(addr(111,’hyd’),addr(222,’bang’))
);
4) Selecting data from table which has
nested table
SQL> Select * from student;
-- This will display nested table column
data along with nested table and adt;
SQL> Select no,name, s.* from student
s1, table(s1.address) s;
-- This will display in general format
5) Instead of s.* you can specify the columns
in nested table
SQL> Select no,name, s.hno,s.city from
student s1,table(s1.address) s;
6) Inserting nested table data to the existing
row
SQL> Insert into table(select address
from student where no=1)
values(addr(555,’chennai’));
7) Update in nested tables
SQL> Update table(select address from
student where no=2) s set s.city=’bombay’

where s.hno = 222;
8) Delete in nested table
SQL> Delete table(select address from
student where no=3) s where s.hno=333;
DATA MODEL
1 ALL_COLL_TYPES
1 ALL_TYPES
1 DBA_COLL_TYPES
1 DBA_TYPES
1 USER_COLL_TYPES
1 USER_TYPES

FLASHBACK QUERY
Used to retrieve the data which has been
already committed with out going for recovery.
Flashbacks are of two types
1 Time base flashback
1 SCN based flashback (SCN stands for
System Change Number)
Ex:
1) Using time based flashback
a) SQL> Select *from student;
-- This will display all the rows
b) SQL> Delete student;
c) SQL> Commit; -- this will commit
the work.
d) SQL> Select *from student;
-- Here it will display nothing
e) Then execute the following procedures
SQL> Exec
dbms_flashback.enable_at_time(sysdate-

2/1440)
f) SQL> Select *from student;
-- Here it will display the lost data
-- The lost data will come but the current
system time was used
g) SQL> Exec dbms_flashback.disable
-- Here we have to disable the flashback
to enable it again
2) Using SCN based flashback
a) Declare a variable to store SCN
SQL> Variable s number
b) Get the SCN
SQL> Exec :s := exec
dbms_flashback.get_system_change_number
c) To see the SCN
SQL> Print s
d) Then execute the following procedures
SQL> Exec
dbms_flashback.enable_at_system_change_nu
mber(:s)
SQL> Exec dbms_flashback.disable

EXTERNAL TABLES
You can user external table feature to access
external files as if they are tables inside the
database.
When you create an external table, you define
its structure and location with in oracle.
When you query the table, oracle reads the
external table and returns the results just as if
the data had been stored with in the database.
ACCESSING EXTERNAL TABLE DATA
To access external files from within oracle, you
must first use the create directory command to
define a directory object pointing to the
external file location
Users who will access the external files must
have the read and write privilege on the
directory.
Ex:
CREATING DIRECTORY AND OS LEVEL FILE

SQL> Sqlplus system/manager
SQL> Create directory saketh_dir as
‘/Visdb/visdb/9.2.0/external’;
SQL> Grant all on directory saketh_dir to
saketh;
SQL> Conn saketh/saketh
SQL> Spool dept.lst
SQL> Select deptno || ‘,’ || dname || ‘,’ ||
loc from dept;
SQL> Spool off
CREATING EXTERNAL TABLE
SQL> Create table dept_ext
(deptno number(2),
Dname varchar(14),
Loc varchar(13))
Organization external ( type
oracle_loader
Default directory
saketh_dir
Access

parameters
( records
delimited by newline
Fields
terminated by “,”
( deptno
number(2),
Dname
varchar(14),
Loc
varchar(13)))
Location (‘/Visdb/visdb/9.2.0/dept.lst’));
SELECTING DATA FROM EXTERNAL TABLE
SQL> select * from dept_ext;
This will read from dept.lst which is a operating
system level file.
LIMITATIONS ON EXTERNAL TABLES
a) You can not perform insert, update, and
delete operations

b) Indexing not possible
a) Constraints not possible
BENEFITS OF EXTERNAL TABLES
a) Queries of external tables complete very
quickly even though a full table scan id
required with each access
a) You can join external tables to each other
or to standard tables
REF DEREF VALUE
REF

1 The ref function allows referencing of
existing row objects.
1 Each of the row objects has an object id
value assigned to it.
1 The object id assigned can be seen by using
ref function.
DEREF
1 The deref function performs opposite
action.
1 It takes a reference value of object id and
returns the value of the row objects.
VALUE
1 Even though the primary table is object
table, still it displays the rows in general
format.
1 To display the entire structure of the
object, this will be used.
Ex:

1) create vendot_adt type
SQL> Create type vendor_adt as object
(vendor_code number(2), vendor_name
varchar(2), vendor_address
varchar(10));/
2) create object tables vendors and vendors1
SQL> Create table vendors of
vendor_adt;
SQL> Create table vendors1 of
vendor_adt;
3) insert the data into object tables
SQL> insert into vendors values(1, ‘a’,
‘hyd’);
SQL> insert into vendors values(2, ‘b’,
‘bang’);
SQL> insert into vendors1 values(3, ‘c’,
‘delhi’);
SQL> insert into vendors1 values(4, ‘d’,
‘chennai’);
4) create another table orders which holds
the vendor_adt type also.
SQL> Create table orders (order_no

number(2), vendor_info ref vendor_adt);
Or
number(2), vendor_info ref vendor_adt with
rowid);
5) insert the data into orders table
The vendor_info column in the following
syntaxes will store object id of any table
which is referenced by vendor_adt object
( both vendors and vendors1).
SQL> insert into orders values(11,(select
ref(v) from vendors v where vendor_code
= 1));
ref(v) from vendors v where vendor_code
= 2));
ref(v1) from vendors1 v1 where
vendor_code = 1));
ref(v1) from vendors1 v1 where

vendor_code = 1));
6) To see the object ids of vendor table
SQL> Select ref(V) from vendors v;
7) If you see the vendor_info of orders it
will show only the object ids not the values,
to see the values
SQL> Select deref(o.vendor_info) from
orders o;
8) Even though the vendors table is object
table it will not show the adt along with
data, to see the data along with the adt
SQL>Select * from vendors;
This will give the data without adt.
SQL>Select value(v) from vendors v;
This will give the columns data along
with the type.
REF CONSTRAINTS
1 Ref can also acts as constraint.
1 Even though vendors1 also holding
vendor_adt, the orders table will store
the object ids of vendors only because it

is constrained to that table only.
1 The vendor_info column in the following
syntaxes will store object ids of vendors
only.
number(2), vendor_info ref vendor_adt scope
is
vendors);
Or
number(2), vendor_info ref vendor_adt
constraint fk
references vendors);
OBJECT VIEWS WITH REFERENCES
To implement the objects and the ref
constraints to the existing tables, what we can
do? Simply drop the both tables and recreate
with objects and ref constraints.
But you can achieve this with out dropping the

tables and without losing the data by creating
object views with references.
Ex:
a) Create the following tables
SQL> Create table student1(no
number(2) primary key,name varchar(2),marks
number(3));
SQL> Create table student2(no
number(2) primary key,hno number(3),city
varchar(10),id number(2),foreign
Key(id) references student1(no));
b) Insert the records into both tables
SQL> insert into student1(1,’a’,100);
SQL> insert into student1(2,’b’,200);
SQL> insert into
student2(11,111,’hyd’,1);
SQL> insert into
student2(12,222,’bang’,2);
SQL> insert into
student2(13,333,’bombay’,1);
c) Create the type

SQL> create or replace type stud as
object(no number(2),name varchar(2),marks
number(3));/
d) Generating OIDs
SQL> Create or replace view student1_ov
of stud with object identifier(or id) (no) as
Select * from Student1;
e) Generating references
SQL> Create or replace view student2_ov
as select no,hno,city,
make_ref(student1_ov,id) id from
Student2;
d) Query the following
SQL> select *from student1_ov;
SQL> select ref(s) from student1_ov s;
SQL> select values(s) from student1_ov;
SQ> select *from student2_ov;
SQL> select deref(s.id) from student2_ov
s;
PARTITIONS
A single logical table can be split into a number

of physically separate pieces based on ranges
of key values. Each of the parts of the table is
called a partition.
A non-partitioned table can not be partitioned
later.
TYPES
1 Range partitions
1 List partitions
1 Hash partitions
1 Sub partitions
ADVANTAGES
1 Reducing downtime for scheduled
maintenance, which allows maintenance
operations to be carried out on selected
partitions while other partitions are
available to users.
1 Reducing downtime due to data failure,
failure of a particular partition will no way
affect other partitions.

1 Partition independence allows for
concurrent use of the various partitions for
various purposes.
ADVANTAGES OF PARTITIONS BY STORING
THEM IN DIFFERENT TABLESPACES
1 Reduces the possibility of data corruption
in multiple partitions.
1 Back up and recovery of each partition can
be done independently.
DISADVANTAGES
1 /Partitioned tables cannot contain any
columns with long or long raw datatypes,
LOB types or object types.
RANGE PARTITIONS
a) Creating range partitioned table

number(2),name varchar(2)) partition by
range(no)
(partition p1 values less than(10),
partition p2 values less than(20), partition p3
values less than(30),partition p4 values
less than(maxvalue));
** if you are using maxvalue for the last
partition, you can not add a partition.
b) Inserting records into range partitioned
table
SQL> Insert into student values(1,’a’); --
this will go to p1
SQL> Insert into student values(11,’b’); --
this will go to p2
SQL> Insert into student values(21,’c’); --
this will go to p3
SQL> Insert into student values(31,’d’); --
this will go to p4
c) Retrieving records from range partitioned
table
SQL> Select *from student;

SQL> Select *from student partition(p1);
d) Possible operations with range partitions
1 Add
1 Drop
1 Truncate
1 Rename
1 Split
1 Move
1 Exchange
e) Adding a partition
SQL> Alter table student add partition p5
values less than(40);
f) Dropping a partition
SQL> Alter table student drop partition p4;
g) Renaming a partition
SQL> Alter table student rename partition
p3 to p6;
h) Truncate a partition
SQL> Alter table student truncate partition
p6;
i) Splitting a partition
SQL> Alter table student split partition p2

at(15) into (partition p21,partition p22);
j) Exchanging a partition
SQL> Alter table student exchange partition
p1 with table student2;
k) Moving a partition
SQL> Alter table student move partition p21
tablespace saketh_ts;
LIST PARTITIONS
a) Creating list partitioned table
list(no)
(partition p1 values(1,2,3,4,5),
partition p2 values(6,7,8,9,10),partition p3
values(11,12,13,14,15), partition p4
values(16,17,18,19,20));
b) Inserting records into list partitioned table
this will go to p1

this will go to p2
SQL> Insert into student values(11,’c’); --
this will go to p3
SQL> Insert into student values(16,’d’);--
this will go to p4
c) Retrieving records from list partitioned table
d) Possible operations with list partitions
8 Add
8 Drop
8 Truncate
8 Rename
8 Move
8 Exchange
values(21,22,23,24,25);

p3 to p6;
p6;
i) Exchanging a partition
p1 with table student2;
j) Moving a partition
SQL> Alter table student move partition p2
tablespace saketh_ts;
HASH PARTITIONS
a) Creating hash partitioned table
hash(no)
partitions 5;
Here oracle automatically gives partition
names like
SYS_P1
SYS_P2

SYS_P3
SYS_P4
SYS_P5
b) Inserting records into hash partitioned table
it will insert the records based on hash
function calculated by taking the partition key
SQL> Insert into student values(1,’a’);
SQL> Insert into student values(6,’b’);
SQL> Insert into student values(11,’c’);
SQL> Insert into student values(16,’d’);
c) Retrieving records from hash partitioned
table
SQL> Select *from student
partition(sys_p1);
d) Possible operations with hash partitions
14 Add
14 Truncate
14 Rename
14 Move
14 Exchange

SQL> Alter table student add partition p6 ;
f) Renaming a partition
SQL> Alter table student rename partition p6
to p7;
g) Truncate a partition
p7;
h) Exchanging a partition
sys_p1 with table student2;
i) Moving a partition
SQL> Alter table student move partition
sys_p2 tablespace saketh_ts;
SUB-PARTITIONS WITH RANGE AND HASH
Subpartitions clause is used by hash only. We
can not create subpartitions with list and hash
partitions.
a) Creating subpartitioned table
number(2),name varchar(2),marks number(3))

Partition by range(no) subpartition by
hash(name) subpartitions 3
(Partition p1 values less
than(10),partition p2 values less than(20));
This will create two partitions p1 and p2 with
three subpartitions for each partition
P1 – SYS_SUBP1
SYS_SUBP2
SYS_SUBP3
P2 – SYS_SUBP4
SYS_SUBP5
SYS_SUBP6
** if you are using maxvalue for the last
partition, you can not add a partition.
b) Inserting records into subpartitioned table
this will go to p1
this will go to p2
c) Retrieving records from subpartitioned table

SQL> Select *from student
subpartition(sys_subp1);
d) Possible operations with subpartitions
19 Add
19 Drop
19 Truncate
19 Rename
19 Split
values less than(30);
p2 to p3;
p1;
i) Splitting a partition
SQL> Alter table student split partition p3

at(15) into (partition p31,partition p32);
DATA MODEL
2 ALL_IND_PARTITIONS
2 ALL_IND_SUBPARTITIONS
2 ALL_TAB_PARTITIONS
2 ALL_TAB_SUBPARTITIONS
2 DBA_IND_PARTITIONS
2 DBA_IND_SUBPARTITIONS
2 DBA_TAB_PARTITIONS
2 DBA_TAB_SUBPARTITIONS
2 USER_IND_PARTITIONS
2 USER_IND_SUBPARTITIONS
2 USER_TAB_PARTITIONS
2 USER_TAB_SUBPARTITIONS
GROUP

BY AND HAVING
GROUP BY
Using group by, we can create groups of
related information.
Columns used in select must be used with
group by, otherwise it was not a group by
expression.
Ex:
SQL> select deptno, sum(sal) from emp
group by deptno;
DEPTNO SUM(SAL)
---------- ----------
10 8750
20 10875
30 9400
SQL> select deptno,job,sum(sal) from emp
group by deptno,job;
DEPTNO JOB SUM(SAL)

---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
20 ANALYST 6000
20 CLERK 1900
20 MANAGER 2975
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
HAVING
This will work as where clause which can be
used only with group by because of absence of
where clause in group by.
Ex:
SQL> select deptno,job,sum(sal) tsal from
emp group by deptno,job having sum(sal) >
3000;
DEPTNO JOB TSAL
---------- --------- ----------

10 PRESIDENT 5000
20 ANALYST 6000
30 SALESMAN 5600
SQL> select deptno,job,sum(sal) tsal from
emp group by deptno,job having sum(sal) >
3000 order by job;
DEPTNO JOB TSAL
---------- --------- ----------
20 ANALYST 6000
10 PRESIDENT 5000
30 SALESMAN 5600
ORDER OF EXECUTION
1 Group the rows together based on group by
clause.
1 Calculate the group functions for each
group.
1 Choose and eliminate the groups based on
the having clause.
1 Order the groups based on the specified

column.
ROLLUP GROUPING CUBE
These are the enhancements to the group by
feature.
USING ROLLUP
This will give the salaries in each department in
each job category along wih the total salary for
individual departments and the total salary of
all the departments.
SQL> Select deptno,job,sum(sal) from emp
group by rollup(deptno,job);

DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
10 8750
20 ANALYST 6000
20 CLERK 1900
20 MANAGER 2975
20 10875
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
30 9400
29025
USING GROUPING
In the above query it will give the total salary
of the individual departments but with a
blank in the job column and gives the total
salary of all the departments with blanks in
deptno and job columns.

To replace these blanks with your desired
string grouping will be used
SQL> select decode(grouping(deptno),1,'All
Depts',deptno),decode(grouping(job),1,'All
jobs',job),sum(sal) from emp group by
rollup(deptno,job);
DECODE(GROUPING(DEPTNO),1,'ALLDEPTS
',DEP DECODE(GR SUM(SAL)
-----------------------------------
---------------------------------- --------------
10 CLERK
1300
10
MANAGER 2450
10
PRESIDENT 5000
10 All jobs
8750
20
ANALYST 6000

20 CLERK
1900
20
MANAGER 2975
20 All jobs
10875
30 CLERK
950
30
MANAGER 2850
30
SALESMAN 5600
30 All jobs
9400
All Depts All
jobs 29025
Grouping will return 1 if the column which is
specified in the grouping function has been
used in rollup.
Grouping will be used in association with
decode.

USING CUBE
This will give the salaries in each department in
each job category, the total salary for
individual departments, the total salary of all
the departments and the salaries in each job
category.
SQL> select decode(grouping(deptno),1,’All
Depts’,deptno),decode(grouping(job),1,’All
Jobs’,job),sum(sal) from emp group by
cube(deptno,job);
DECODE(GROUPING(DEPTNO),1,'ALLDEPTS
',DEP DECODE(GR SUM(SAL)
-----------------------------------
------------------------------------ ------------
10 CLERK
1300
10 MANAGER
2450

10 PRESIDENT
5000
10 All Jobs
8750
20 ANALYST
6000
20 CLERK
1900
20 MANAGER
2975
20 All Jobs
10875
30 CLERK
950
30 MANAGER
2850
30 SALESMAN
5600
30 All Jobs
9400
All Depts
ANALYST 6000

All Depts CLERK
4150
All Depts
MANAGER 8275
All Depts
PRESIDENT 5000
All Depts
SALESMAN 5600
All Depts All Jobs
29025
SET OPERATORS

TYPES
1 Union
1 Union all
1 Intersect
1 Minus
UNION
This will combine the records of multiple tables
having the same structure.
Ex:
SQL> select * from student1 union select *
from student2;
UNION ALL
This will combine the records of multiple tables
having the same structure but including
duplicates.
Ex:
SQL> select * from student1 union all select

* from student2;
INTERSECT
This will give the common records of multiple
tables having the same structure.
Ex:
SQL> select * from student1 intersect select
* from student2;
MINUS
This will give the records of a table whose
records are not in other tables having the same
structure.
Ex:
SQL> select * from student1 minus select *
from student2;

A view is a database object that is a logical
representation of a table. It is delivered from a
table but has no storage of its own and often
may be used in the same manner as a table.
A view takes the output of the query and treats
it as a table, therefore a view can be thought of
as a stored query or a virtual table.
TYPES
1 Simple view
1 Complex view
Simple view can be created from one table
where as complex view can be created from
multiple tables.
WHY VIEWS?
1 Provides additional level of security by
restricting access to a predetermined set of
rows and/or columns of a table.
1 Hide the data complexity.
1 Simplify commands for the user.

VIEWS WITHOUT DML
1 Read only view
1 View with group by
1 View with aggregate functions
1 View with rownum
1 Partition view
1 View with distinct
Ex:
SQL> Create view dept_v as select *from
dept with read only;
SQL> Create view dept_v as select deptno,
sum(sal) t_sal from emp group by deptno;
SQL> Create view stud as select rownum
no, name, marks from student;
SQL> Create view student as select *from
student1 union select *from student2;
SQL> Create view stud as select distinct
no,name from student;
VIEWS WITH DML

1 View with not null column -- insert with
out not null column not possible
-- update not
null column to null is not possible
-- delete
possible
2 View with out not null column which was in
base table -- insert not possible
-- update, delete possible
3 View with expression -- insert , update not
possible
-- delete possible
4 View with functions (except aggregate) --
insert, update not possible
-- delete possible
5 View was created but the underlying table
was dropped then we will get the message
like “ view has errors ”.
5 View was created but the base table has

been altered but still the view was with the
initial definition, we have to replace the
view to affect the changes.
5 Complex view (view with more than one
table) -- insert not possible
--
update, delete possible (not always)
CREATING VIEW WITHOUT HAVING THE BASE
TABLE
SQL> Create force view stud as select *From
student;
-- Once the base table was created then
the view is validated.
VIEW WITH CHECK OPTION CONSTRAINT
SQL> Create view stud as select *from student
where marks = 500 with check option
constraint Ck;
- Insert possible with marks value as 500
- Update possible excluding marks column

- Delete possible
DROPPING VIEWS
SQL> drop view dept_v;
DATA MODEL
ALL_VIEW
DBA_VIEW
USER_VIEWS

SYNONYM AND SEQUENCE
SYNONYM
A synonym is a database object, which is used
as an alias for a table, view or sequence.
TYPES
3 Private
3 Public
Private synonym is available to the particular
user who creates.
Public synonym is created by DBA which is
available to all the users.
ADVANTAGES

1 Hide the name and owner of the object.
1 Provides location transparency for remote
objects of a distributed database.
CREATE AND DROP
SQL> create synonym s1 for emp;
SQL> create public synonym s2 for emp;
SQL> drop synonym s1;
SEQUENCE
A sequence is a database object, which can
generate unique, sequential integer values.
It can be used to automatically generate
primary key or unique key values.
A sequence can be either in an ascending or
descending order.
Syntax:
Create sequence <seq_name> [increment
bty n] [start with n] [maxvalue n]
[minvalue n]
[cycle/nocycle] [cache/nocache];

By defalult the sequence starts with 1,
increments by 1 with minvalue of 1 and with
nocycle, nocache.
Cache option pre-alloocates a set of sequence
numbers and retains them in memory for faster
access.
Ex:
SQL> create sequence s;
SQL> ,
USING SEQUENCE
SQL> create table student(no number(2),name
varchar(10));
SQL> insert into student values(s.nextval,
‘saketh’);
1 Initially currval is not defined and nextval
is starting value.
1 After that nextval and currval are always
equal.

CREATING ALPHA-NUMERIC SEQUENCE
SQL> create sequence s start with 111234;
SQL> Insert into student values (s.nextval ||
translate
(s.nextval,’1234567890’,’abcdefghij’));
ALTERING SEQUENCE
We can alter the sequence to perform the
following.
1 Set or eliminate minvalue or maxvalue.
1 Change the increment value.
1 Change the number of cached sequence
numbers.
Ex:
SQL> alter sequence s minvalue 5;
SQL> alter sequence s increment by 2;
SQL> alter sequence s cache 10;
DROPPING SEQUENCE
SQL> drop sequence s;

JOINS
1 The purpose of a join is to combine the
data across tables.
1 A join is actually performed by the where
clause which combines the specified rows
of tables.
1 If a join involves in more than two tables
then oracle joins first two tables based on
the joins condition and then compares the
result with the next table and so on.
TYPES
1 Equi join
1 Non-equi join
1 Self join
1 Natural join
1 Cross join
1 Outer join
Ø Left outer
Ø Right outer
Ø Full outer

1 Inner join
1 Using clause
1 On clause
Assume that we have the following tables.
SQL> select * from dept;
DEPTNO DNAME LOC
------ ---------- ----------
10 mkt hyd
20 fin bang
30 hr bombay
SQL> select * from emp;
EMPNO ENAME JOB MGR DEPTNO
---------- ---------- ---------- ----------
----------
111 saketh analyst 444
10

222 sudha clerk 333
20
333 jagan manager 111
10
444 madhu engineer 222
40
EQUI JOIN
A join which contains an ‘=’ operator in the
joins condition.
Ex:
SQL> select empno,ename,job,dname,loc
from emp e,dept d where e.deptno=d.deptno;
EMPNO ENAME JOB
DNAME LOC
---------- ---------- ----------
---------- ----------
111 saketh analyst
mkt hyd
333 jagan manager

mkt hyd
222 sudha clerk
fin bang
USING CLAUSE
SQL> select empno,ename,job ,dname,loc from
emp e join dept d using(deptno);
EMPNO ENAME JOB
DNAME LOC
---------- ---------- ----------
---------- ----------
111 saketh analyst
mkt hyd
333 jagan manager
mkt hyd
222 sudha clerk
fin bang
ON CLAUSE
SQL> select empno,ename,job,dname,loc from
emp e join dept d on(e.deptno=d.deptno);

EMPNO ENAME JOB
DNAME LOC
---------- ---------- ----------
---------- ----------
111 saketh analyst
mkt hyd
333 jagan manager
mkt hyd
222 sudha clerk
fin bang
NON-EQUI JOIN
A join which contains an operator other than
‘=’ in the joins condition.
Ex:
from emp e,dept d where e.deptno =
d.deptno;
EMPNO ENAME JOB
DNAME LOC

---------- ---------- ----------
---------- ----------
222 sudha clerk mkt
hyd
444 madhu engineer mkt
hyd
444 madhu engineer fin
bang
444 madhu engineer hr
bombay
SELF JOIN
Joining the table itself is called self join.
Ex:
SQL> select
e1.empno,e2.ename,e1.job,e2.deptno from
emp e1,emp e2 where
e1.empno=e2.mgr;
EMPNO ENAME JOB DEPTNO
---------- ---------- ---------- ----------

111 jagan analyst 10
222 madhu clerk 40
333 sudha manager 20
444 saketh engineer 10
NATURAL JOIN
Natural join compares all the common columns.
Ex:
from emp natural join dept;
EMPNO ENAME JOB DNAME
LOC
---------- ---------- ---------- ----------
----------
111 saketh analyst mkt
hyd
333 jagan manager mkt
hyd
222 sudha clerk fin
bang

CROSS JOIN
This will gives the cross product.
Ex:
from emp cross join dept;
LOC
---------- ---------- ---------- ----------
----------
hyd
222 sudha clerk mkt
hyd
hyd
444 madhu engineer mkt
hyd
111 saketh analyst fin
bang
222 sudha clerk fin

bang
333 jagan manager fin
bang
444 madhu engineer fin
bang
111 saketh analyst hr
bombay
222 sudha clerk hr
bombay
333 jagan manager hr
bombay
444 madhu engineer hr
bombay
OUTER JOIN
Outer join gives the non-matching records
along with matching records.
LEFT OUTER JOIN
This will display the all matching records and
the records which are in left hand side table

those that are not in right hand side table.
Ex:
from emp e left outer join dept d
on(e.deptno=d.deptno);
Or
from emp e,dept d where
e.deptno=d.deptno(+);
LOC
---------- ---------- ---------- ----------
----------
hyd
hyd
222 sudha clerk fin
bang
444 madhu engineer

RIGHT OUTER JOIN
the records which are in right hand side table
those that are not in left hand side table.
Ex:
from emp e right outer join dept d
Or
from emp e,dept d where e.deptno(+) =
d.deptno;
LOC
---------- ---------- ---------- ----------
----------
hyd

hyd
222 sudha clerk fin
bang
hr
bombay
FULL OUTER JOIN
the non-matching records from both tables.
Ex:
from emp e full outer join dept d
LOC
---------- ---------- ---------- ----------
----------
hyd

hyd
222 sudha clerk fin
bang
444 madhu engineer
hr
bombay
INNER JOIN
This will display all the records that have
matched.
Ex:
from emp inner join dept using(deptno);
LOC
---------- ---------- ---------- ----------
----------
hyd

hyd
222 sudha clerk fin
bang
SUBQUERIES AND EXISTS
SUBQUERIES
1 Nesting of queries, one within the other is
termed as a subquery.
1 A statement containing a subquery is called
a parent query.
1 Subqueries are used to retrieve data from
tables that depend on the values in the
table itself.
TYPES
1 Single row subqueries
1 Multi row subqueries
1 Multiple subqueries
1 Correlated subqueries

SINGLE ROW SUBQUERIES
In single row subquery, it will return one value.
Ex:
SQL> select * from emp where sal > (select
sal from emp where empno = 7566);
EMPNO ENAME JOB MGR
HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ----------
------------ ------- ---------- ----------
7788 SCOTT ANALYST 7566 19-
APR-87 3000 20
7839 KING PRESIDENT 17-
NOV-81 5000 10
7902 FORD ANALYST 7566 03-
DEC-81 3000 20
MULTI ROW SUBQUERIES
In multi row subquery, it will return more than
one value. In such cases we should include
operators like any, all, in or not in between the

comparision operator and the subquery.
Ex:
SQL> select * from emp where sal > any
(select sal from emp where sal between 2500
and 4000);
EMPNO ENAME JOB MGR
---------- ---------- --------- ----------
----------- -------- ---------- ----------
7566 JONES MANAGER 7839 02-
APR-81 2975 20
APR-87 3000 20
NOV-81 5000 10
DEC-81 3000 20
SQL> select * from emp where sal > all
(select sal from emp where sal between 2500
and 4000);

EMPNO ENAME JOB MGR
---------- ---------- --------- ----------
------------- ------ ---------- ----------
NOV-81 5000 10
MULTIPLE SUBQUERIES
There is no limit on the number of subqueries
included in a where clause. It allows nesting of
a query within a subquery.
Ex:
SQL> select * from emp where sal = (select
max(sal) from emp where sal < (select
max(sal) from emp));
EMPNO ENAME JOB MGR
---------- ---------- --------- ----------
------------ ------- ---------- ----------

APR-87 3000 20
DEC-81 3000 20
CORRELATED SUBQUERIES
A subquery is evaluated once for the entire
parent statement where as a correlated
subquery is evaluated once for every row
processed by the parent statement.
Ex:
SQL> select distinct deptno from emp e
where 5 <= (select count(ename) from emp
where e.deptno = deptno);
DEPTNO
----------
20
30
EXISTS
Exists function is a test for existence. This is a
logical test for the return of rows from a query.

Ex:
Suppose we want to display the department
numbers which has more than 4
employees.
SQL> select deptno,count(*) from emp
group by deptno having count(*) > 4;
DEPTNO COUNT(*)
--------- ----------
20 5
30 6
From the above query can you want to
display the names of employees?
SQL> select deptno,ename, count(*) from
emp group by deptno,ename having count(*)
> 4;
no rows selected
The above query returns nothing because
combination of deptno and ename never

return more than one count.
The solution is to use exists which follows.
SQL> select deptno,ename from emp e1
where exists (select * from emp e2
where e1.deptno=e2.deptno group by
e2.deptno having count(e2.ename) > 4)
order by deptno,ename;
DEPTNO ENAME
---------- ----------
20 ADAMS
20 FORD
20 JONES
20 SCOTT
20 SMITH
30 ALLEN
30 BLAKE
30 JAMES
30 MARTIN
30 TURNER
30 WARD

NOT EXISTS
SQL> select deptno,ename from emp e1 where
not exists (select * from emp e2
where e1.deptno=e2.deptno group by
e2.deptno having count(e2.ename) > 4) order
by deptno,ename;
DEPTNO ENAME
--------- ----------
10 CLARK
10 KING
10 MILLER
WALKUP TREES AND INLINE VIEW
WALKUP TREES
Using hierarchical queries, you can retrieve
data based on a natural hierarchical

relationship between rows in a table. However,
where a hierarchical relationship exists
between the rows of a table, a process called
tree walking enables the hierarchy to be
constructed.
Ex:
SQL> select ename || '==>' || prior ename,
level from emp start with ename = 'KING'
connect by prior empno=mgr;
ENAME||'==>'||PRIORENAM LEVEL
------------------------------------ --------
KING==> 1
JONES==>KING 2
SCOTT==>JONES 3
ADAMS==>SCOTT 4
FORD==>JONES 3
SMITH==>FORD 4
BLAKE==>KING 2
ALLEN==>BLAKE 3
WARD==>BLAKE 3

MARTIN==>BLAKE 3
TURNER==>BLAKE 3
JAMES==>BLAKE 3
CLARK==>KING 2
MILLER==>CLARK 3
In the above
Start with clause specifies the root row of the
table.
Level pseudo column gives the 1 for root, 2 for
child and so on.
Connect by prior clause specifies the columns
which has parent-child relationship.
INLINE VIEW OR TOP-N ANALYSIS
In the select statement instead of table name,
replacing the select statement is known as
inline view.
Ex:
SQL> Select ename, sal, rownum rank from
(select *from emp order by sal);

ENAME SAL RANK
---------- ---------- ----------
SMITH 800 1
JAMES 950 2
ADAMS 1100 3
WARD 1250 4
MARTIN 1250 5
MILLER 1300 6
TURNER 1500 7
ALLEN 1600 8
CLARK 2450 9
BLAKE 2850 10
JONES 2975 11
SCOTT 3000 12
FORD 3000 13
KING 5000 14
LOCKS
Locks are the mechanisms used to prevent

destructive interaction between users
accessing same resource simultaneously. Locks
provides high degree of data concurrency.
TYPES
1 Row level locks
1 Table level locks
ROW LEVEL LOCKS
In the row level lock a row is locked exclusively
so that other cannot modify the row until the
transaction holding the lock is committed or
rolled back. This can be done by using
select..for update clause.
Ex:
SQL> select * from emp where sal > 3000
for update of comm.;
TABLE LEVEL LOCKS
A table level lock will protect table data
thereby guaranteeing data integrity when data

is being accessed concurrently by multiple
users. A table lock can be held in several
modes.
1 Share lock
1 Share update lock
1 Exclusive lock
SHARE LOCK
A share lock locks the table allowing other
users to only query but not insert, update or
delete rows in a table. Multiple users can place
share locks on the same resource at the same
time.
Ex:
SQL> lock table emp in share mode;
SHARE UPDATE LOCK
It locks rows that are to be updated in a table.
It permits other users to concurrently query,
insert , update or even lock other rows in the
same table. It prevents the other users from

updating the row that has been locked.
Ex:
SQL> lock table emp in share update mode;
EXCLUSIVE LOCK
Exclusive lock is the most restrictive of tables
locks. When issued by any user, it allows the
other user to only query. It is similar to share
lock but only one user can place exclusive lock
on a table at a time.
Ex:
SQL> lock table emp in share exclusive
mode;
NOWAIT
If one user locked the table without nowait
then another user trying to lock the same table
then he has to wait until the user who has
initially locked the table issues a commit or
rollback statement. This delay could be avoided

by appending a nowait clause in the lock table
command.
Ex:
SQL> lock table emp in exclusive mode
nowait.
DEADLOCK
A deadlock occurs when two users have a lock
each on separate object, and they want to
acquire a lock on the each other’s object. When
this happens, the first user has to wait for the
second user to release the lock, but the second
user will not release it until the lock on the first
user’s object is freed. In such a case, oracle
detects the deadlock automatically and solves
the problem by aborting one of the two
transactions.
INDEXES
Index is typically a listing of keywords

accompanied by the location of information on
a subject. We can create indexes explicitly to
speed up SQL statement execution on a table.
The index points directly to the location of the
rows containing the value.
WHY INDEXES?
Indexes are most useful on larger tables, on
columns that are likely to appear in where
clauses as simple equality.
TYPES
1 Unique index
1 Non-unique index
1 Btree index
1 Bitmap index
1 Composite index
1 Reverse key index
1 Function-based index
1 Descending index
1 Domain index

1 Object index
1 Cluster index
1 Text index
1 Index organized table
1 Partition index
v Local index
ü Local prefixed
ü Local non-prefixed
2 Global index
ü Global prefixed
ü Global non-prefixed
UNIQUE INDEX
Unique indexes guarantee that no two rows of
a table have duplicate values in the columns
that define the index. Unique index is
automatically created when primary key or
unique constraint is created.
Ex:
SQL> create unique index stud_ind on
student(sno);

NON-UNIQUE INDEX
Non-Unique indexes do not impose the above
restriction on the column values.
Ex:
SQL> create index stud_ind on
student(sno);
BTREE INDEX or ASCENDING INDEX
The default type of index used in an oracle
database is the btree index. A btree index is
designed to provide both rapid access to
individual rows and quick access to groups of
rows within a range. The btree index does this
by performing a succession of value
comparisons. Each comparison eliminates many
of the rows.
Ex:
student(sno);

BITMAP INDEX
This can be used for low cardinality columns:
that is columns in which the number of distinct
values is small when compared to the number
of the rows in the table.
Ex:
SQL> create bitmap index stud_ind on
student(sex);
COMPOSITE INDEX
A composite index also called a concatenated
index is an index created on multiple columns
of a table. Columns in a composite index can
appear in any order and need not be adjacent
columns of the table.
Ex:
SQL> create bitmap index stud_ind on
student(sno, sname);

REVERSE KEY INDEX
A reverse key index when compared to
standard index, reverses each byte of the
column being indexed while keeping the
column order. When the column is indexed in
reverse mode then the column values will be
stored in an index in different blocks as the
starting value differs. Such an arrangement can
help avoid performance degradations in
indexes where modifications to the index are
concentrated on a small set of blocks.
Ex:
SQL> create index stud_ind on student(sno,
reverse);
We can rebuild a reverse key index into normal
index using the noreverse keyword.
Ex:
SQL> alter index stud_ind rebuild
noreverse;

FUNCTION BASED INDEX
This will use result of the function as key
instead of using column as the value for the
key.
Ex:
student(upper(sname));
DESCENDING INDEX
The order used by B-tree indexes has been
ascending order. You can categorize data in B-
tree index in descending order as well. This
feature can be useful in applications where
sorting operations are required.
Ex:
SQL> create index stud_ind on student(sno
desc);

TEXT INDEX
Querying text is different from querying data
because words have shades of meaning,
relationships to other words, and opposites.
You may want to search for words that are near
each other, or words that are related to thers.
These queries would be extremely difficult if all
you had available was the standard relational
operators. By extending SQL to include text
indexes, oracle text permits you to ask very
complex questions about the text.
To use oracle text, you need to create a text
index on the column in which the text is stored.
Text index is a
of tables and indexes that store information
about the text stored in the column.
TYPES
There are several different types of indexes
available in oracle 9i. The first, CONTEXT is

supported in oracle 8i as well as oracle 9i. As of
oracle 9i, you can use the CTXCAT text index fo
further enhance your text index management
and query capabilities.
1 CONTEXT
1 CTXCAT
1 CTXRULE
The CTXCAT index type supports the
transactional synchronization of data between
the base table and its text index. With
CONTEXT indexes, you need to manually tell
oracle to update the values in the text index
after data changes in base table. CTXCAT index
types do not generate score values during the
text queries.
HOW TO CREATE TEXT INDEX?
You can create a text index via a special
version of the create index comman. For
context index, specify the ctxsys.context index

type and for ctxcat index, specify the
ctxsys.ctxcat index type.
Ex:
Suppose you have a table called BOOKS with
the following columns
Title, Author, Info.
SQL> create index book_index on books(info)
indextype is ctxsys.context;
indextype is ctxsys.ctxcat;
TEXT QUERIES
Once a text index is created on the info column
of BOOKS table, text-searching capabilities
increase dynamically.
CONTAINS & CATSEARCH
CONTAINS function takes two parameters – the
column name and the search string.

Syntax:
Contains(indexed_column, search_str);
If you create a CTXCAT index, use the
CATSEARCH function in place of CONTAINS.
CATSEARCH takes three parameters – the
column name, the search string and the index
set.
Syntax:
Contains(indexed_column, search_str,
index_set);
HOW A TEXT QEURY WORKS?
When a function such as CONTAINS or
CATSEARCH is used in query, the text portion of
the query is processed by oracle text. The
remainder of the query is processed just like a
regular query within the database. The result of
the text query processing and the regular query
processing are merged to return a single set of
records to the user.

SEARCHING FOR AN EXACT MATCH OF A WORD
The following queries will search for a word
called ‘prperty’ whose score is greater than
zero.
SQL> select * from books where contains(info,
‘property’) > 0;
SQL> select * from books where
catsearch(info, ‘property’, null) > 0;
Suppose if you want to know the score of the
‘property’ in each book, if score values for
individual searches range from 0 to 10 for each
occurrence of the string within the text then
use the score function.
SQL> select title, score(10) from books where
contains(info, ‘property’, 10) > 0;
SEARCHING FOR AN EXACT MATCH OF
MULTIPLE WORDS
The following queries will search for two

words.
‘property AND harvests’) > 0;
catsearch(info, ‘property AND harvests’, null) >
0;
Instead of using AND you could have used an
ampersand(&). Before using this method, set
define off so the & character will not be seen as
part of a variable name.
SQL> set define off
‘property & harvests’) > 0;
catsearch(info, ‘property harvests’, null) > 0;
The following queries will search for more than
two words.
‘property AND harvests AND workers’) > 0;

catsearch(info, ‘property harvests workers’,
null) > 0;
The following queries will search for either of
the two words.
‘property OR harvests’) > 0;
Instead of OR you can use a vertical line (|).
‘property | harvests’) > 0;
catsearch(info, ‘property | harvests’, null) > 0;
In the following queries the
ACCUM(accumulate) operator adds together
the scores of the individual searches and
compares the accumulated score to the
threshold value.

‘property ACCUM harvests’) > 0;
catsearch(info, ‘property ACCUM harvests’,
null) > 0;
Instead of OR you can use a comma(,).
‘property , harvests’) > 0;
catsearch(info, ‘property , harvests’, null) > 0;
In the following queries the MINUS operator
subtracts the score of the second term’s search
from the score of the first term’s search.
‘property MINUS harvests’) > 0;
catsearch(info, ‘property NOT harvests’, null) >
0;
Instead of MINUS you can use – and instead of
NOT you can use ~.

‘property - harvests’) > 0;
catsearch(info, ‘property ~ harvests’, null) > 0;
SEARCHING FOR AN EXACT MATCH OF A
PHRASE
The following queries will search for the
phrase. If the search phrase includes a
reserved word within oracle text, the you must
use curly braces ({}) to enclose text.
‘transactions {and} finances’) > 0;
catsearch(info, ‘transactions {and} finances’,
null) > 0;
You can enclose the entire phrase within curly
braces, in which case any reserved words
within the phrase will be treated as part of the
search criteria.

‘{transactions and finances}’) > 0;
catsearch(info, ‘{transactions and finances}’,
null) > 0;
SEARCHING FOR WORDS THAT ARE NEAR EACH
OTHER
The following queries will search for the words
that are in between the search terms.
‘workers NEAR harvests’) > 0;
Instead of NEAR you can use ;.
‘workers ; harvests’) > 0;
In CONTEXT index queries, you can specify the
maximum number of words between the search
terms.

‘NEAR((workers, harvests),10)’ > 0;
USING WILDCARDS DURING SEARCHES
You can use wildcards to expand the list of
valid search terms used during your query. Just
as in regular text-string wildcard processing,
two wildcards are available.
% - percent sign; multiple-character
wildcard
_ - underscore; single-character wildcard
‘worker%’) > 0;
‘work___’) > 0;
SEARCHING FOR WORDS THAT SHARE THE
SAME STEM
Rather than using wildcards, you can use stem-

expansion capabilities to expand the list of text
strings. Given the ‘stem’ of a word, oracle will
expand the list of words to search for to include
all words having the same stem. Sample
expansions are show here.
Play - plays playing played playful
‘$manage’) > 0;
SEARCHING FOR FUZZY MATCHES
A fuzzy match expands the specified search
term to include words that are spelled similarly
but that do not necessarily have the same word
stem. Fuzzy matches are most helpful when the
text contains misspellings. The misspellings
can be either in the searched text or in the
search string specified by the user during the
query.
The following queries will not return anything
because its search does not contain the word

‘hardest’.
‘hardest’) > 0;
It does, however, contains the word ‘harvest’.
A fuzzy match will return the books containing
the word ‘harvest’ even though ‘harvest’ has a
different word stem thant the word used as the
search term.
To use a fuzzy match, precede the search term
with a question mark, with no space between
the question mark and the beginning of the
search term.
‘?hardest’) > 0;
SEARCHING FOR WORDS THAT SOUND LIKE
OTHER WORDS
SOUNDEX, expands search terms based on how
the word sounds. The SOUNDEX expansion

method uses the same text-matching logic
available via the SOUNDEX function in SQL.
To use the SOUNDEX option, you must precede
the search term with an exclamation mark(!).
‘!grate’) > 0;
INDEX SYNCHRONIZATION
When using CONTEXT indexes, you need to
manage the text index contents; the text
indexes are not updated when the base table is
updated. When the table was updated, its text
index is out of sync with the base table. To sync
of the index, execute the SYNC_INDEX
procedure of the CTX_DDL package.
SQL> exec
CTX_DDL.SYNC_INDEX(‘book_index’);
INDEX SETS

Historically, problems with queries of text
indexes have occurred when other criteria are
used alongside text searches as part of the
where clause. To improve the mixed query
capability, oracle features index sets. The
indexes within the index set may be structured
relational columns or on text columns.
To create an index set, use the CTX_DDL
package to create the index set and add
indexes to it. When you create a text index, you
can then specify the index set it belongs to.
SQL> exec
CTX_DDL.CREATE_INDEX_SET(‘books_index_s
et’);
The add non-text indexes.
SQL> exec
CTX_DDL.ADD_INDEX(‘books_index_set’,
‘title_index’);
Now create a CTXCAT text index. Specify

ctxsys.ctxcat as the index type, and list the
index set in the parameters clause.
indextype is ctxsys.ctxcat
parameters(‘index set books_index_set’);
INDEX-ORGANIZED TABLE
An index-organized table keeps its data sorted
according to the primary key column values for
the table. Index-organized tables store their
data as if the entire table was stored in an
index.
An index-organized table allows you to store
the entire table’s data in an index.
Ex:
SQL> create table student (sno
number(2),sname varchar(10),smarks
number(3)
constraint pk primary key(sno)
organization index;

PARTITION INDEX
Similar to partitioning tables, oracle allows you
to partition indexes too. Like table partitions,
index partitions could be in different
tablespaces.
LOCAL INDEXES
1 Local keyword tells oracle to create a
separte index for each partition.
1 In the local prefixed index the partition key
is specified on the left prefix. When the
underlying table is partitioned baes on, say
two columns then the index can be prefixed
on the first column specified.
1 Local prefixed indexes can be unique or
non unique.
1 Local indexes may be easier to manage
than global indexes.
Ex:
SQL> create index stud_index on

student(sno) local;
GLOBAL INDEXES
1 A global index may contain values from
multiple partitions.
1 An index is global prefixed if it is
partitioned on the left prefix of the index
columns.
1 The global clause allows you to create a
non-partitioned index.
1 Global indexes may perform uniqueness
checks faster than local (partitioned)
indexes.
1 You cannot create global indexes for hash
partitions or subpartitions.
Ex:
SQL> create index stud_index on
student(sno) global;
Similar to table partitions, it is possible to
move them from one device to another. But

unlike table partitions, movement of index
partitions requires individual reconstruction of
the index or each partition (only in the case of
global index).
Ex:
SQL> alter index stud_ind rebuild partition
p2
1 Index partitions cannot be dropped
manually.
1 They are dropped implicitly when the data
they refer to is dropped from the
partitioned table.
MONITORING USE OF INDEXES
Once you turned on the monitoring the use of
indexes, then we can check whether the table
is hitting the index or not.
To monitor the use of index use the follwing
syntax.

Syntax:
alter index index_name monitoring usage;
then check for the details in V$OBJECT_USAGE
view.
If you want to stop monitoring use the
following.
Syntax:
alter index index_name nomonitoring
usage;
DATA MODEL
1 ALL_INDEXES
1 DBA_INDEXES
1 USER_INDEXES
1 ALL_IND-COLUMNS
1 DBA-IND_COLUMNS
1 USER_IND_COLUMNS
1 ALL_PART_INDEXES
1 DBA_PART_INDEXES

1 USER_PART_INDEXES
1 V$OBJECT_USAGE
SQL*PLUS COMMNANDS
These commands does not require statement
terminator and applicable to the sessions ,
those will be automatically cleared when

session was closed.
BREAK
This will be used to breakup the data
depending on the grouping.
Syntax:
Break or bre [on <column_name> on
report]
COMPUTE
This will be used to perform group functions on
the data.
Syntax:
Compute or comp [group_function of
column_name on breaking_column_name or
report]
TTITLE
This will give the top title for your report. You

can on or off the ttitle.
Syntax:
Ttitle or ttit [left | center | right]
title_name skip n other_characters
Ttitle or ttit [on or off]
BTITLE
This will give the bottom title for your report.
You can on or off the btitle.
Syntax:
Btitle or btit [left | center | right]
title_name skip n other_characters
Btitle or btit [on or off]
Ex:
SQL> bre on deptno skip 1 on report
SQL> comp sum of sal on deptno
SQL> comp sum of sal on report
SQL> ttitle center 'EMPLOYEE DETAILS'
skip1 center '----------------'
SQL> btitle center '** THANKQ **'

SQL> select * from emp order by deptno;
Output:
EMPLOYEE
DETAILS
-----------------------
EMPNO ENAME JOB MGR
---------- ---------- --------- -------
-------------- -------- ---------- ----------
7782 CLARK MANAGER 7839 09-
JUN-81 2450 10
NOV-81 5000
7934 MILLER CLERK 7782 23-
JAN-82 1300
---------- **********
8750 sum

7369 SMITH CLERK 7902 17-
DEC-80 800 20
7876 ADAMS CLERK 7788 23-
MAY-87 1100
DEC-81 3000
APR-87 3000
7566 JONES MANAGER 7839 02-
APR-81 2975
---------- **********
10875 sum
7499 ALLEN SALESMAN 7698 20-
FEB-81 1600 300 30
7698 BLAKE MANAGER 7839 01-
MAY-81 2850
7654 MARTIN SALESMAN 7698 28-
SEP-81 1250 1400
7900 JAMES CLERK 7698 03-

DEC-81 950
7844 TURNER SALESMAN 7698 08-
SEP-81 1500 0
7521 WARD SALESMAN 7698 22-
FEB-81 1250 500
---------- **********
9400 sum
----------
sum
29025
** THANKQ **
CLEAR
This will clear the existing buffers or break or
computations or columns formatting.
Syntax:
Clear or cle buffer | bre | comp | col;

Ex:
SQL> clear buffer
Buffer cleared
SQL> clear bre
Breaks cleared
SQL> clear comp
Computes cleared
SQL> clear col
Columns cleared
CHANGE
This will be used to replace any strings in SQL
statements.
Syntax:
Change or c/old_string/new_string
If the old_string repeats many times then
new_string replaces the first string only.
Ex:
SQL> select * from det;

select * from det
*
ERROR at line 1:
ORA-00942: table or view does not
exist
SQL> c/det/dept
1* select * from dept
SQL> /
DEPTNO DNAME LOC
---------- ---------------- -----------
10 ACCOUNTING NEW YORK
20 RESEARCH ALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
COLUMN
This will be used to increase or decrease the
width of the table columns.
Syntax:
Column or col <column_name> format

<num_format|text_format>
Ex:
SQL> col deptno format 999
SQL> col dname format a10
SAVE
This will be used to save your current SQL
statement as SQL Script file.
Syntax:
Save or sav <file_name>.[extension]
replace or rep
If you want to save the filename with existing
filename the you have to use replace option.
By default it will take sql as the extension.
Ex:
SQL> save ss
Created file ss.sql
SQL> save ss replace
Wrote file ss.sql

EXECUTE
This will be used to execute stored
subprograms or packaged subprograms.
Syntax:
Execute or exec <subprogram_name>
Ex:
SQL> exec sample_proc
SPOOL
This will record the data when you spool on,
upto when you say spool off. By default it will
give lst as extension.
Syntax:
Spool on | off | out | <file_name>.
[Extension]
Ex:
SQL> spool on

DEPTNO DNAME LOC
--------- -------------- ----------
20 RESEARCH DALLAS
30 SALES CHICAGO
SQL> spool off
SQL> ed on.lst
DEPTNO DNAME LOC
--------- -------------- ----------
20 RESEARCH DALLAS
30 SALES CHICAGO
SQL> spool off
LIST

This will give the current SQL statement.
Syntax:
List or li [start_line_number]
[end_line_number]
Ex:
SQL> select
2 *
3 from
4 dept;
SQL> list
1 select
2 *
3 from
4* dept
SQL> list 1
1* select
SQL> list 3
3* from
SQL> list 1 3

1 select
2 *
3* from
INPUT
This will insert the new line to the current SQL
statement.
Syntax:
Input or in <string>
Ex:
SQL> select *
SQL> list
1* select *
SQL> input from dept
SQL> list
1 select *
2* from dept
APPEND
This will adds a new string to the existing

string in the SQL statement without any space.
Syntax:
Append or app <string>
Ex:
SQL> select *
SQL> list
1* select *
SQL> append from dept
SQL> list
DELETE
This will delete the current SQL statement
lines.
Syntax:
Delete or del <start_line_number>
[<end_line_number>]
Ex:

SQL> select
2 *
3 from
4 dept
5 where
6 deptno
7 >10;
SQL> list
1 select
2 *
3 from
4 dept
5 where
6 deptno
7* >10
SQL> del 1
SQL> list
1 *
2 from
3 dept
4 where
5 deptno

6* >10
SQL> del 2
SQL> list
1 *
2 dept
3 where
4 deptno
5* >10
SQL> del 2 4
SQL> list
1 *
2* >10
SQL> del
SQL> list
1 *
VARIABLE
This will be used to declare a variable.
Syntax:
Variable or var <variable_name>
<variable_type>

Ex:
SQL> var dept_name varchar(15)
SQL> select dname into dept_name from
dept where deptno = 10;
PRINT
This will be used to print the output of the
variables that will be declared at SQL level.
Syntax:
Print <variable_name>
Ex:
SQL> print dept_name
DEPT_NAME
--------------
ACCOUNTING
START
This will be used to execute SQL scripts.

Syntax:
start <filename_name>.sql
Ex:
SQL> start ss.sql
SQL> @ss.sql -- this will execute sql
script files only.
HOST
This will be used to interact with the OS level
from SQL.
Syntax:
Host [operation]
Ex:
SQL> host
SQL> host dir
SHOW
Using this, you can see several commands that
use the set command and status.

Syntax:
Show all | <set_command>
Ex:
SQL> show all
appinfo is OFF and set to "SQL*Plus"
arraysize 15
autocommit OFF
autoprint OFF
autorecovery OFF
autotrace OFF
blockterminator "." (hex 2e)
btitle OFF and is the first few characters of
the next SELECT statement
cmdsep OFF
colsep " "
compatibility version NATIVE
concat "." (hex 2e)
copycommit 0
COPYTYPECHECK is ON
define "&" (hex 26)
describe DEPTH 1 LINENUM OFF INDENT

ON
echo OFF
editfile "afiedt.buf"
embedded OFF
escape OFF
FEEDBACK ON for 6 or more rows
flagger OFF
flush ON
SQL> sho verify
verify OFF
RUN
This will runs the command in the buffer.
Syntax:
Run | /
Ex:
SQL> run
SQL> /
STORE

This will save all the set command statuses in a
file.
Syntax:
Store set <filename>.[extension] [create]
| [replace] | [append]
Ex:
SQL> store set my_settings.scmd
Created file my_settings.scmd
SQL> store set my_settings.cmd replace
Wrote file my_settings.cmd
SQL> store set my_settings.cmd append
Appended file to my_settings.cmd
FOLD_AFTER
This will fold the columns one after the other.
Syntax:
Column <column_name> fold_after
[no_of_lines]
Ex:

SQL> col deptno fold_after 1
SQL> col dname fold_after 1
SQL> col loc fold_after 1
SQL> set heading off
10
ACCOUNTING
NEW YORK
20
RESEARCH
DALLAS
30
SALES
CHICAGO
40
OPERATIONS
BOSTON
FOLD_BEFORE
This will fold the columns one before the other.

Syntax:
Column <column_name> fold_before
[no_of_lines]
DEFINE
This will give the list of all the variables
currently defined.
Syntax:
Define [variable_name]
Ex:
SQL> define
DEFINE _DATE = "16-MAY-07"
(CHAR)
DEFINE _CONNECT_IDENTIFIER = "oracle"
(CHAR)
DEFINE _USER = "SCOTT" (CHAR)
DEFINE _PRIVILEGE = "" (CHAR)
DEFINE _SQLPLUS_RELEASE =
"1001000200" (CHAR)
DEFINE _EDITOR = "Notepad" (CHAR)

DEFINE _O_VERSION = "Oracle
Database 10g Enterprise Edition Release
10.1.0.2.0 –
Production With the Partitioning, OLAP and
Data Mining
options" (CHAR)
DEFINE _O_RELEASE = "1001000200"
(CHAR)
SET COMMANDS
These commands does not require statement
terminator and applicable to the sessions ,
those will be automatically cleared when
session was closed.
LINESIZE
This will be used to set the linesize. Default
linesize is 80.
Syntax:
Set linesize <value>

Ex:
SQL> set linesize 100
PAGESIZE
This will be used to set the pagesize. Default
pagesize is 14.
Syntax:
Set pagesize <value>
Ex:
SQL> set pagesize 30
DESCRIBE
This will be used to see the object’s structure.
Syntax:
Describe or desc <object_name>
Ex:
SQL> desc dept

Name
Null? Type
---------------------------------------------------
-------------- ---------------------
DEPTNO
NOT NULL NUMBER(2)
DNAME
VARCHAR2(14)
LOC
VARCHAR2(13)
PAUSE
When the displayed data contains hundreds or
thousands of lines, when you select it then it
will automatically scrolls and displays the last
page data. To prevent this you can use this
pause option. By using this it will display the
data correspoinding to the pagesize with a
break which will continue by hitting the return
key. By default this will be off.
Syntax:

Set pause on | off
Ex:
SQL> set pause on
FEEDBACK
This will give the information regarding
howmany rows you selected the object. By
default the feedback message will be displayed,
only when the object contains more than 5
rows.
Syntax:
Set feedback <value>
Ex:
SQL> set feedback 4
DEPTNO DNAME LOC
---------- -------------- -------------
20 RESEARCH DALLAS

30 SALES CHICAGO
4 rows selected.
HEADING
If you want to display data without headings,
then you can achieve with this. By default
heading is on.
Syntax:
Set heading on | off
Ex:
SQL> set heading off
20 RESEARCH DALLAS
30 SALES CHICAGO
SERVEROUTPUT

This will be used to display the output of the
PL/SQL programs. By default this will be off.
Syntax:
Set serveroutput on | off
Ex:
SQL> set serveroutput on
TIME
This will be used to display the time. By default
this will be off.
Syntax:
Set time on | off
Ex:
SQL> set time on
19:56:33 SQL>
TIMING

This will give the time taken to execute the
current SQL statement. By default this will be
off.
Syntax:
Set timing on | off
Ex:
SQL> set timing on
DEPTNO DNAME LOC
---------- -------------- -------------
20 RESEARCH DALLAS
30 SALES CHICAGO
Elapsed: 00:00:00.06
SQLPROMPT
This will be used to change the SQL prompt.

Syntax:
Set sqlprompt <prompt>
Ex:
SQL> set sqlprompt 'ORACLE>'
ORACLE>
SQLCASE
This will be used to change the case of the SQL
statements. By default the case is mixed.
Syntax:
Set sqlcase upper | mixed | lower
Ex:
SQL> set sqlcase upper
SQLTERMINATOR
This will be used to change the terminator of
the SQL statements. By default the terminator
is ;.

Syntax:
Set sqlterminator <termination_character>
Ex:
SQL> set sqlterminator :
SQL> select * from dept:
DEFINE
By default if the & character finds then it will
treat as bind variable and ask for the input.
Suppose your want to treat it as a normal
character while inserting data, then you can
prevent this by using the define option. By
default this will be on
Syntax:
Set define on | off
Ex:
SQL>insert into dept
values(50,'R&D','HYD');
Enter value for d:

old 1: insert into dept
values(50,'R&D','HYD')
new 1: INSERT INTO DEPT
VALUES(50,'R','HYD')
SQL> set define off
SQL>insert into dept
values(50,'R&D','HYD'); -- here it won’t ask
for value
NEWPAGE
This will shows how many blank lines will be
left before the report. By default it will leave
one blank line.
Syntax:
Set newpage <value>
Ex:
SQL> set newpage 10
The zero value for newpage does not produce
zero blank lines instead it switches to a special

property which produces a top-of-form
character (hex 13) just before the date on each
page. Most modern printers respond to this by
moving immediately to the top of the next
page, where the priting of the report will begin.
HEADSEP
This allow you to indicate where you want to
break a page title or a column heading that
runs longer than one line. The default heading
separator is vertical bar (|).
Syntax:
Set headsep <separation_char>
Ex:
DEPTNO DNAME LOC
---------- -------------- -------------
20 RESEARCH DALLAS
30 SALES CHICAGO

SQL> set headsetp !
SQL> col dname heading 'DEPARTMENT !
NAME'
SQL> /
DEPARTMENT
DEPTNO NAME LOC
---------- ----------------- ----------
20 RESEARCH DALLAS
30 SALES CHICAGO
ECHO
When using a bind variable, the SQL statement
is maintained by echo. By default this is off.
Syntax:
Set echo on | off
VERIFY

When using a bind variable, the old and new
statements will be maintained by verify. By
default this is on.
Syntax:
Set verify on | off
Ex:
SQL> select * from dept where deptno =
&dno;
Enter value for dno: 10
old 1: select * from dept where deptno =
&dno
new 1: select * from dept where deptno =
10
DEPTNO DNAME LOC
---------- ---------------- -----------
SQL> set verify off
SQL> select * from dept where deptno =
&dno;

Enter value for dno: 20
DEPTNO DNAME LOC
---------- ------------- -----------
20 RESEARCH DALLAS
PNO
This will give displays the page numbers. By
default the value would be zero.
Ex:
SQL> col hiredate new_value xtoday
noprint format a1 trunc
SQL> ttitle left xtoday right 'page' sql.pno
SQL> select * from emp where deptno =
10;
09-JUN-81
page 1
EMPNO ENAME JOB MGR
SAL COMM DEPTNO

---------- ---------- --------------- ---------
----- ---------- ----------
7782 CLARK MANAGER 7839
2450 10
7839 KING PRESIDENT
5000 10
7934 MILLER CLERK 7782
1300 10
In the above noprint tells SQLPLUS not to
display this column when it prints the results of
the SQL statement. Dates that have been
reformatted by TO_CHAR get a default width of
about 100 characters. By changing the format
to a1 trunc, you minimize this effect.
NEW_VALUE inserts contents of the column
retrieved by the SQL statement into a variable
called xtoday.

SPECIAL FILES
LOGIN.sql
If you would like SQLPLUS to define your own
environmental settings, put all the required
commands in a file named login.sql. This is a
special filename that SQLPLUS always looks for
whenever it starts up. If it finds login.sql, it
executes any commands in it as if you had
entered then by hand. You can put any
command in login.sql that you can use in
SQLPLUS, including SQLPLUS commands and

SQL statements. All ot them executed before
SQLPLUS gives you the SQL> prompt.
GLOGIN.sql
This is used in the same ways as LOGIN.sql but
to establish default SQLPLUS settings for all
users of a database.
IMPORTANT QUERIES
1) To find the nth row of a table
SQL> Select *from emp where rowid =

(select max(rowid) from emp where
rownum
<= 4);
Or
SQL> Select *from emp where rownum <=
4 minus select *from emp where rownum
<= 3;
2) To find duplicate rows
SQL> Select *from emp where rowid in
(select max(rowid) from emp group by
empno, ename, mgr, job, hiredate,
comm, deptno, sal);
Or
SQL> Select
empno,ename,sal,job,hiredate,comm ,
count(*) from emp group by
empno,ename,sal,job,hiredate,comm
having count(*) >=1;
3) To delete duplicate rows

SQL> Delete emp where rowid in (select
max(rowid) from emp group by
empno,ename,mgr,job,hiredate,sal,comm,de
ptno);
4) To find the count of duplicate rows
SQL> Select ename, count(*) from emp
group by ename having count(*) >= 1;
5) How to display alternative rows in a table?
SQL> select *from emp where (rowid,0)
in (select rowid,mod(rownum,2) from emp);
6) Getting employee details of each
department who is drawing maximum sal?
SQL> select *from emp where
(deptno,sal) in
( select deptno,max(sal) from emp
group by deptno);
7) How to get number of employees in each

department , in which department is having
more than 2500 employees?
SQL> Select deptno,count(*) from emp
group by deptno having count(*) >2500;
8) To reset the time to the beginning of the day
SQL> Select
to_char(trunc(sysdate),’dd-mon-yyyy hh:mi:ss
am’) from dual;
9) To find nth maximum sal
SQL> Select *from emp where sal in
(select max(sal) from (select *from emp
order
by sal) where rownum <= 5);

INTRODUCTION
CHARACTERSTICS
1 Highly structured, readable and accessible
language.
1 Standard and Protable language.
1 Embedded language.
1 Improved execution authority.
10g FEATURES
1 Optimized compiler

.
To change the optimizer settings for the
entire database, set the database
parameter PLSQL_OPTIMIZE_LEVEL. Valid
settings are as follows
0 - No optimization
1 - Moderate optimization
2 - Aggressive optimization
These settings are also modifiable for the
current session.
SQL> alter session set
plsql_optimze_level=2;
Oracle retains optimizer settings on a
module-by-module basis. When you
recompile a particular module with
nondefault settings, the settings will stick
allowing you to recompile later on using
REUSE SETTINGS.
SQL> Alter procedure proc compile
plsql_optimize_level=1;

SQL> Alter procedure proc compile reuse
settings;
2 Compile-time warnings.
Starting with oracle database 10g release 1
you can enable additional compile-time
warnings to help make your programs more
robust. The compiler can detect potential
runtime problems with your code, such as
identifying lines of code that will never be
run. This process, also known as lint
checking.
To enable these warnings fo the entire
database, set the database parameter
PLSQL_WARNINGS. These settings are also
modifiable for the current session.
SQL> alter session set plsql_warnings =
‘enable:all’;
The above can be achieved using the built-
in package DBMS_WARNING.

3 Conditional compilation.
Conditional compilation allows the compiler
to allow to compile selected parts of a
program based on conditions you provide
with the $IF directive.
4 Support for non-sequential collections in
FORALL.
4 Improved datatype support.
6 Backtrace an exception to its line number.
When handling an error, how can you find
the line number on which the error was
originally raised?
In earlier release, the only way to do this
was allow you exception to go unhandled
and then view the full error trace stack.
Now you can call
DBMS_UTILITY.FORMAT_ERROR_BACKTRA
CE function to obtain that stack and

manipulate it programmatically within your
program.
7 Set operators for nested tables.
8 Support for regular expressions.
Oracle database 10g supports the use of
regular expressions inside PL/SQL code via
four new built-in functions.
ü REGEXP_LIKE
ü REGEXP_INSTR
ü REGEXP_SUBSTR
ü REGEXP_REPLACE
9 Programmer-defined quoting mechanism.
Starting with oracle database 10g release
1, you can define your own quoting
mechanism for string literals in both SQL
and PL/SQL.
Use the characters q’(q followed by a single
quote) to note the programmer-defined

deliemeter for you string literal.
Ex:
DECLARE
v varchar(10) := 'computer';
BEGIN
dbms_output.put_line(q'*v = *' ||
v);
dbms_output.put_line(q'$v = $' ||
v);
END;
Output:
v = computer
v = computer
10 Many new built-in packages.
DBMS_SCHEDULER
Represents a major update to DBMS_JOB.
DBMS_SCHEDULER provides much
improved functionality for scheduling and
executing jobs defined via stored

procedures.
DBMS_CRYPTO
Offers the ability to encrypt and decrypt
common oracle datatype, including RAWs,
BLOBs, and CLOBs. It also provides
globalization support for encrypting data
across different charactersets.
DBMS_MONITOR
Provides an API to control additional
tracing and statistics gathering of sessions.
DBMS_WARNING
Provides an API into the PL/SQL compiler
warnings module, allowing you to read and
change settings that control which
warnings are suppressed, displayed, or
treated as errors.
STANDARD PACKAGE

Oracle has defined in this special package.
Oracle defines quite a few identifiers in this
package, including built-in exceptions,
functions and subtypes.
You can reference the built-in form by prefixing
it with STANDARD.
The basic unit in any PL/SQL program is block.
All PL/SQL programs are composed of blocks
which can occur sequentially or nested.
BLOCK STRUCTURE
Declare
-- declarative section
Begin
-- executable section
Exception
-- exception section
End;
In the above, declarative and exception
sections are optional.

BLOCK TYPES
1 Anonymous blocks
1 Named blocks
ü Labeled blocks
ü Subprograms
ü Triggers
ANONYMOUS BLOCKS
Anonymous blocks implies basic block
structure.
Ex:
BEGIN
Dbms_output.put_line(‘My first
program’):
END;
LABELED BLOCKS
Labeled blocks are anonymous blocks with a

label which gives a name to the block.
Ex:
<<my_bloock>>
BEGIN
Dbms_output.put_line(‘My first
program’):
END;
SUBPROGRAMS
Subprograms are procedures and functions.
They can be stored in the database as stand-
alone objects, as part of package or as methods
of an object type.
TRIGGERS
Triggers consists of a PL/SQL block that is
associated with an event that occur in the
database.
NESTED BLOCKS

A block can be nested within the executable or
exception section of an outer block.
IDENTIFIERS
Identifiers are used to name PL/SQL objects,
such as variables, cursors, types and
subprograms. Identifiers consists of a letter,
optionally followed by any sequence of
characters, including letters, numbers, dollar
signs, underscores, and pound signs only. The
maximum length for an identifier is 30
characters.
QUOTED IDENTIFIERS
If you want to make an identifier case
sensitive, include characters such as spaces or
use a reserved word, you can enclose the
identifier in double quotation marks.
Ex:
DECLARE
"a" number := 5;

"A" number := 6;
BEGIN
dbms_output.put_line('a = ' || a);
dbms_output.put_line('A = ' || A);
END;
Output:
a = 6
A = 6
COMMENTS
Comments improve readability and make your
program more understandable. They are
ignored by the PL/SQL compiler. There are two
types of comments available.
1 Single line comments
1 Multiline comments
SINGLE LINE COMMENTS
A single-line comment can start any point on a
line with two dashes and continues until the

end of the line.
Ex:
BEGIN
Dbms_output.put_line(‘hello’);
-- sample program
END;
MULTILINE COMMENTS
Multiline comments start with the /* delimiter
and ends with */ delimiter.
Ex:
BEGIN
Dbms_output.put_line(‘hello’);
/* sample program */
END;
VARIABLE DECLERATIONS
Variables can be declared in declarative section
of the block;
Ex:

DECLARE
a number;
b number := 5;
c number default 6;
CONSTANT DECLERATIONS
To declare a constant, you include the
CONSTANT keyword, and you must supply a
default value.
Ex:
DECLARE
b constant number := 5;
c constant number default 6;
NOT NULL CLAUSE
You can also specify that the variable must be
not null.
Ex:
DECLARE
b constant number not null:= 5;

c number not null default 6;
ANCHORED DECLERATIONS
PL/SQL offers two kinds of anchoring.
1 Scalar anchoring
1 Record anchoring
SCALAR ANCHORING
Use the %TYPE attribute to define your
variable based on table’s column of some other
PL/SQL scalar variable.
Ex:
DECLARE
dno dept.deptno%type;
Subtype t_number is number;
a t_number;
Subtype t_sno is student.sno
%type;
V_sno t_sno;
RECORD ANCHORING

Use the %ROWTYPE attribute to define your
record structure based on a table.
Ex:
`DECLARE
V_dept dept%rowtype;
BENEFITS OF ANCHORED DECLARATIONS
1 Synchronization with database columns.
1 Normalization of local variables.
PROGRAMMER-DEFINED TYPES
With the SUBTYPE statement, PL/SQL allows
you to define your own subtypes or aliases of
predefined datatypes, sometimes referred to as
abstract datatypes.
There are two kinds of subtypes.
1 Constrained
1 Unconstrained
CONSTRAINED SUBTYPE

A subtype that restricts or constrains the
values normally allowd by the datatype itself.
Ex:
Subtype positive is binary_integer range
1..2147483647;
In the above declaration a variable that is
declared as positive can store only ingeger
greater than zero even though binary_integer
ranges from -2147483647..+2147483647.
UNCONSTRAINED SUBTYPE
A subtype that does not restrict the values of
the original datatype in variables declared with
the subtype.
Ex:
Subtype float is number;
DATATYPE CONVERSIONS
PL/SQL can handle conversions between

different families among the datatypes.
Conversion can be done in two ways.
1 Explicit conversion
1 Implicit conversion
EXPLICIT CONVERSION
This can be done using the built-in functions
available.
IMPLICIT CONVERSION
PL/SQL will automatically convert between
datatype families when possible.
Ex:
DECLARE
a varchar(10);
BEGIN
select deptno into a from dept
where dname='ACCOUNTING';
END;
In the above variable a is char type and deptno

is number type even though, oracle will
automatically converts the numeric data into
char type assigns to the variable.
PL/SQL can automatically convert between
1 Characters and numbers
1 Characters and dates
VARIABLE SCOPE AND VISIBILITY
The scope of a variable is the portion of the
program in which the variable can be accessed.
For PL/SQL variables, this is from the variable
declaration until the end of the block. When a
variable goes out of scope, the PL/SQL engine
will free the memory used to store the variable.
The visibility of a variable is the portion of the
program where the variable can be accessed
without having to qualify the reference. The
visibility is always within the scope. If it is out
of scope, it is not visible.
Ex1:

DECLARE
a number; -- scope of a
BEGIN
--------
DECLARE
b number;-- scope of b
BEGIN
-----
END;
------
END;
Ex2:
DECLARE
a number;
b number;
BEGIN
-- a , b available here
DECLARE
b char(10);
BEGIN
-- a and char type b is available
here

END;
-----
END;
Ex3:
<<my_block>>
DECLARE
a number;
b number;
BEGIN
-- a , b available here
DECLARE
b char(10);
BEGIN
-- a and char type b is available
here
-- number type b is available
using <<my_block>>.b
END;
------
END;
PL/SQL CONTROL STRUCTURES

PL/SQL has a variety of control structures that
allow you to control the behaviour of the block
as it runs. These structures include conditional
statements and loops.
1 If-then-else
1 Case
ü Case with no else
ü Labeled case
ü Searched case
1 Simple loop
1 While loop
1 For loop
1 Goto and Labels
IF-THEN-ELSE
Syntax:
If <condition1> then
Sequence of statements;
Elsif <condition1> then

……
Else
End if;
Ex:
DECLARE
dno number(2);
BEGIN
select deptno into dno from dept
where dname = 'ACCOUNTING';
if dno = 10 then
dbms_output.put_line('Location
is NEW YORK');
elsif dno = 20 then
dbms_output.put_line('Locati
on is DALLAS');
elsif dno = 30 then
on is CHICAGO');
else

on is BOSTON');
end if;
END;
Output:
Location is NEW YORK
CASE
Syntax:
Case test-variable
When value1 then sequence of
statements;
statements;
……
When valuen then sequence of
statements;
Else sequence of statements;
End case;
Ex:
DECLARE

dno number(2);
BEGIN
case dno
when 10 then
dbms_output.put_line('
Location is NEW YORK');
when 20 then
Location is DALLAS');
when 30 then
Location is CHICAGO');
else
Location is BOSTON');
end case;
END;
Output:

CASE WITHOUT ELSE
Syntax:
Case test-variable
statements;
statements;
……
statements;
End case;
Ex:
DECLARE
dno number(2);
BEGIN
case dno
when 10 then

when 20 then
when 30 then
when 40 then
end case;
END;
Output:
LABELED CASE
Syntax:
<<label>>
Case test-variable

statements;
statements;
……
statements;
End case;
Ex:
DECLARE
dno number(2);
BEGIN
<<my_case>>
case dno
when 10 then
when 20 then

when 30 then
when 40 then
end case my_case;
END;
Output:
SEARCHED CASE
Syntax:
Case
When <condition1> then sequence of
statements;
When <condition2> then sequence of
statements;
……
When <conditionn> then sequence of
statements;

End case;
Ex:
DECLARE
dno number(2);
BEGIN
case dno
when dno = 10 then
dbms_output.put_line(
'Location is NEW YORK');
when dno = 20 then
'Location is DALLAS');
when dno = 30 then
'Location is CHICAGO');
when dno = 40 then
'Location is BOSTON');
end case;

END;
Output:
SIMPLE LOOP
Syntax:
Loop
Exit when <condition>;
End loop;
In the syntax exit when <condition> is
equivalent to
If <condition> then
Exit;
End if;
Ex:
DECLARE
i number := 1;
BEGIN
loop

dbms_output.put_line('i = ' || i);
i := i + 1;
exit when i > 5;
end loop;
END;
Output:
i = 1
i = 2
i = 3
i = 4
i = 5
WHILE LOOP
Syntax:
While <condition> loop
End loop;
Ex:
DECLARE
i number := 1;

BEGIN
While i <= 5 loop
dbms_output.put_line('i = ' ||
i);
i := i + 1;
end loop;
END;
Output:
i = 1
i = 2
i = 3
i = 4
i = 5
FOR LOOP
Syntax:
For <loop_counter_variable> in
low_bound..high_bound loop
End loop;

Ex1:
BEGIN
For i in 1..5 loop
i);
end loop;
END;
Output:
i = 1
i = 2
i = 3
i = 4
i = 5
Ex2:
BEGIN
For i in reverse 1..5 loop
i);
end loop;
END;
Output:

i = 5
i = 4
i = 3
i = 2
i = 1
NULL STATEMENT
Usually when you write a statement in a
program, you want it to do something. There
are cases, however, when you want to tell
PL/SQL to do absolutely nothing, and that is
where the NULL comes.
The NULL statement deos nothing except pass
control to the next executable statement.
You can use NULL statement in the following
situations.
1 Improving program readability.
Sometimes, it is helpful to avoid any
ambiguity inherent in an IF statement that
doesn’t cover all possible cases. For example,

when you write an IF statement, you do not
have to include an ELSE clause.
2 Nullifying a raised exception.
When you don’t want to write any special
code to handle an exception, you can use the
NULL statement to make sure that a raised
exception halts execution of the current
PL/SQL block but does not propagate any
exceptions to enclosing blocks.
3 Using null after a label.
In some cases, you can pair NULL with GOTO
to avoid having to execute additional
statements. For example, I use a GOTO
statement to quickly move to the end of my
program if the state of my data indicates that
no further processing is required. Because I
do not have to do anything at the termination
of the program, I place a NULL statement
after the label because at least one
executable statement is required there. Even
though NULL deos nothing, it is still an

executable statement.
GOTO AND LABELS
Syntax:
Goto label;
Where label is a label defined in the PL/SQL
block. Labels are enclosed in double angle
brackets. When a goto statement is evaluated,
control immediately passes to the statement
identified by the label.
Ex:
BEGIN
For i in 1..5 loop
i);
if i = 4 then
goto exit_loop;
end if;
end loop;
<<exit_loop>>
Null;

END;
Output:
i = 1
i = 2
i = 3
i = 4
RESTRICTIONS ON GOTO
1 It is illegal to branch into an inner block,
loop.
1 At least one executable statement must
follow.
1 It is illegal to branch into an if statement.
1 It is illegal to branch from one if statement
to another if statement.
1 It is illegal to branch from exception block
to the current block.
PRAGMAS
Pragmas are compiler directives. They serve as
instructions to the PL/SQL compiler. The

compiler will act on the pragma during the
compilation of the block.
Syntax:
PRGAMA instruction_to_compiler.
PL/SQL offers several pragmas:
1 AUTONOMOUS_TRANSACTION
1 EXCEPTION_INIT
1 RESTRICT_REFERENCES
1 SERIALLY_REUSABLE

SUBPROGRAMS
PROCEDURES
A procedure is a module that performs one or
more actions.
Syntax:
Procedure [schema.]name [(parameter1
[,parameter2 …])]
[authid definer |
current_user] is
-- [declarations]
Begin
-- executable statements
[Exception
-- exception handlers]

End [name];
In the above authid clause defines whether the
procedure will execute under the authority of
the definer of the procedure or under the
authority of the current user.
FUNCTIONS
A function is a module that returns a value.
Syntax:
Function [schema.]name [(parameter1
[,parameter2 …])]
Return return_datatype
[authid definer | current_user]
[deterministic]
[parallel_enable] is
-- [declarations]
Begin
-- executable statements
[Exception
-- exception handlers]

End [name];
In the above authid clause defines whether the
procedure will execute under the authority of
the definer of the procedure or under the
authority of the current user.
Deterministic clause defines, an optimization
hint that lets the system use a saved copy of
the function’s return result, if available. The
quety optimizer can choose whether to use the
saved copy or re-call the function.
Parallel_enable clause defines, an optimization
hint that enables the function to be executed in
parallel when called from within SELECT
statement.
PARAMETER MODES
1 In (Default)
1 Out
1 In out
IN

In parameter will act as pl/sql constant.
OUT
1 Out parameter will act as unintialized
variable.
1 You cannot provide a default value to an
out parameter.
1 Any assignments made to out parameter
are rolled back when an exception is raised
in the program.
1 An actual parameter corresponding to an
out formal parameter must be a variable.
IN OUT
5 In out parameter will act as initialized
variable.
5 An actual parameter corresponding to an in
out formal parameter must be a variable.

DEFAULT PARAMETERS
Default Parameters will not allow in the
beginning and middle.
Out and In Out parameters can not have
default values.
Ex:
procedure p(a in number default 5, b in
number default 6, c in number default 7) –
valid
procedure p(a in number, b in number default
6, c in number default 7) – valild
procedure p(a in number, b in number, c in
number default 7) – valild
procedure p(a in number, b in number default
6, c in number) – invalild
number default 6, c in number) – invalild
number, c in number) – invalild
NOTATIONS

Notations are of two types.
Ø Positional notation
Ø Name notation
We can combine positional and name notation
but positional notation can not be followed by
the name notation.
Ex:
Suppose we have a procedure proc(a
number,b number,c number) and we have one
anonymous block which contains v1,v2, and
v3;
SQL> exec proc (v1,v2,v3) --
Positional notation
SQL> exec proc (a=>v1,b=>v2,c=>v3) --
Named notation
FORMAL AND ACTUAL PARAMETERS
1 Parametes which are in calling subprogram

are actual parameters.
1 Parametes which are in called subprogram
are formal parameters.
1 If any subprogram was called, once the call
was completed then the values of formal
parameters are copied to the actual
parameters.
Ex1:
CREATE OR REPLACE PROCEDURE
SAMPLE(a in number,b out number,c in
out
num
ber) is
BEGIN
dbms_output.put_line('After call');
dbms_output.put_line('a = ' || a ||'
b = ' || b || ' c = ' || c);
b := 10;
c := 20;
dbms_output.put_line('After
assignment');

dbms_output.put_line('a = ' || a ||'
b = ' || b || ' c = ' || c);
END SAMPLE;
DECLARE
v1 number := 4;
v2 number := 5;
v3 number := 6;
BEGIN
dbms_output.put_line('Before call');
dbms_output.put_line('v1 = ' || v1
|| ' v2 = ' || v2 || ' v3 = ' || v3);
sample(v1,v2,v3);
completion of call');
|| ' v2 = ' || v2 || ' v3 = ' || v3);
END;
Output:
Before call
v1 = 4 v2 = 5 v3 = 6
After call

a = 4 b = c = 6
After assignment
a = 4 b = 10 c = 20
After completion of call
v1 = 4 v2 = 10 v3 = 20
Ex2:
CREATE OR REPLACE FUN(a in
number,b out number,c in out number)
return
number IS
BEGIN
dbms_output.put_line('After call');
dbms_output.put_line('a = ' || a || '
b = ' || b || ' c = ' || c);
dbms_output.put_line('Before
assignement Result = ' ||
(a*nvl(b,1)*c));
b := 5;
c := 7;
assignment');
dbms_output.put_line('a = ' || a ||

' b = ' || b || ' c = ' || c);
return (a*b*c);
END FUN;
DECLARE
v1 number := 1;
v2 number := 2;
v3 number := 3;
v number;
BEGIN
dbms_output.put_line('Before
call');
|| ' v2 = ' || v2 || ' v3 = ' || v3);
v := fun(v1,v2,v3);
dbms_output.put_line('After call
completed');
|| ' v2 = ' || v2 || ' v3 = ' || v3);
dbms_output.put_line('Result = ' ||
v);
END;

Output:
Before call
v1 = 1 v2 = 2 v3 = 3
After call
a = 1 b = c = 3
Before assignement Result = 3
After assignment
a = 1 b = 5 c = 7
After call completed
v1 = 1 v2 = 5 v3 = 7
Result = 35
RESTRICTIONS ON FORMAL PARAMETERS
1 By declaring with specified size in actual
parameters.
1 By declaring formal parameters with %type
specifier.
USING NOCOPY
1 Nocopy is a hint, not a command. This
means that the compiler might silently

decide that it can’t fulfill your request for a
nocopy parameter.
1 The copying from formal to actual can be
restricted by issuing nocopy qualifier.
1 To pass the out and in out parameters by
reference use nocopy qualifier.
Ex:
CREATE OR REPLACE PROCEDURE PROC(a
in out nocopy number) IS
BEGIN
----
END PROC;
CALL AND EXEC
Call is a SQL statement, which can be used to
execute subprograms like exec.
Syntax:
Call subprogram_name([argument_list])
[into host_variable];
7 The parantheses are always required, even

if the subprogram takes no arguments.
7 We can not use call with out and in out
parameters.
7 Call is a SQL statement, it is not valid inside
a PL/SQL block;
7 The INTO clause is used for the output
variables of functions only.
7 We can not use ‘exec’ with out or in out
parameters.
7 Exec is not valid inside a PL/SQL block;
Ex1:
CREATE OR REPLACE PROC IS
BEGIN
dbms_output.put_line('hello
world');
END PROC;
Output:
SQL> call proc();
hello world

Ex2:
CREATE OR REPLACE PROC(a in
number,b in number) IS
BEGIN
dbms_output.put_line('a = ' || a ||
' b = ' || b);
END PROC;
Output:
SQL> call proc(5,6);
a = 5 b = 6
Ex3:
CREATE OR REPLACE FUNCTION FUN
RETURN VARCHAR IS
BEGIN
return 'hello world';
END FUN;
Output:
SQL> variable v varchar(20)
SQL> call fun() into :v;
SQL> print v

hello world
CALL BY REFERENCE AND CALL BY VALUE
4 In parameters by default call by reference
where as out and in out call by value.
4 When parameter passed by reference, a
pointer to the actual parameter is passed to
the corresponding formal parameter.
4 When parameter passed by value it copies
the value of the actual parameter to the
formal parameter.
4 Call by reference is faster than the call by
value because it avoids the copying.
SUBPROGRAMS OVERLOADING
1 Possible with different number of
parameters.
1 Possible with different types of data.
1 Possible with same type with objects.
1 Can not be possible with different types of
modes.

1 We can overload local subprograms also.
Ex:
SQL> create or replace type t1 as object(a
number);/
SQL> create or replace type t1 as object(a
number);/
DECLARE
i t1 := t1(5);
j t2 := t2(5);
PROCEDURE P(m t1) IS
BEGIN
dbms_output.put_line('a = ' ||
m.a);
END P;
PROCEDURE P(n t2) IS
BEGIN
dbms_output.put_line('b = ' ||
n.b);
END P;
PROCEDURE PRODUCT(a number,b
number) IS

BEGIN
dbms_output.put_line('Product of
a,b = ' || a * b);
END PRODUCT;
PROCEDURE PRODUCT(a number,b
number,c number) IS
BEGIN
dbms_output.put_line('Product of
a,b = ' || a * b * c);
END PRODUCT;
BEGIN
p(i);
p(j);
product(4,5);
product(4,5,6);
END;
Output:
a = 5
b = 5
Product of a,b = 20
Product of a,b = 120

BENEFITS OF OVERLOADING
Ø Supporting many data combinations
Ø Fitting the program to the user.
RESTRICTIONS ON OVERLOADING
1 Overloaded programs with parameter lists
that differ only by name must be called
using named notation.
1 The parameter list of overloaded programs
must differ by more than parameter mode.
1 All of the overloaded programs must be
defined within the same PL/SQL scope or
block.
1 Overloaded functions must differ by more
than their return type.
IMPORTANT POINTS ABOUT SUBPROGRAMS
8 When a stored subprogram is created, it is
stored in the data dictionary.
8 The subprogram is stored in compile form

which is known as p-code in addition to the
source text.
8 The p-code has all of the references in the
subprogram evaluated, and the source code
is translated into a form that is easily
readable by PL/SQL engine.
8 When the subprogram is called, the p-code
is read from the disk, if necessary, and
executed.
8 Once it reads from the disk, the p-code is
stored in the shared pool portion of the
system global area (SGA), where it can be
accessed by multiple users as needed.
8 Like all of the contents of the shared pool,
p-code is aged out of the shared pool
according to a least recently used (LRU)
algorithm.
8 Subprograms can be local.
8 Local subprograms must be declared in the
declarative section of PL/SQL block and
called from the executable section.
8 Subprograms can not have the declarative

section separately.
8 Stored subprograms can have local
subprograms;
8 Local subprograms also can have local
subprograms.
8 If the subprogram contains a variable with
the same name as the column name of the
table then use the dot method to
differentiate (subprogram_name.sal).
8 Subprograms can be invalidated.
PROCEDURES V FUNCTIONS
13 Procedures may return through out and in
out parameters where as function must
return.
13 Procedures can not have return clause
where as functions must.
13 We can use call statement directly for
executing procedure where as we need to
declare a variable in case of functions.
13 Functions can use in select statements
where as procedures can not.

13 Functions can call from reports
environment where as procedures can not.
13 We can use exec for executing procedures
where as functions can not.
13 Function can be used in dbms_output
where as procedure can not.
13 Procedure call is a standalone executable
statement where as function call is a part
of an executable statement.
STORED V LOCAL SUBPROGRAMS
1 The stored subprogram is stored in
compiled p-code in the database, when the
procedure is called it does not have to be
compiled.
The local subprogram is compiled as part
of its containing block. If the containing
block is anonymous and is run multiple
times, the subprogram has to be compiled
each time.
1 Stored subprograms can be called from any

block submitted by a user who has execute
privileges on the subprogram.
Local subprograms can be called only from
the block containing the subprogram.
2 By keeping the stored subprogram code
separate from the calling block, the calling
block is shorter and easier to understand.
The local subprogram and the calling block
are one and the same, which can lead to
part confusion. If a change to the calling
block is made, the subprogram will be
recompiled as of the recompilation of the
containing block.
3 The compiled p-code can be pinned in the
shared pool using the
DBMS_SHARED_POOL Package. This can
improve performance.
Local subprograms cannot be pinned in
the shared pool by themselves.
4 Stand alone stored subprograms can not be
overloaded, but packaged subprograms can
be overloaded within the same package.

4 Local subprograms can be overloaded
within the same block.
Ex1:
CREATE OR REPLACE PROCEDURE P IS
BEGIN
dbms_output.put_line('Stored
subprogram');
END;
Output:
SQL> exec p
Stored subprogram
Ex2:
DECLARE
PROCEDURE P IS
BEGIN
dbms_output.put_line('Local
subprogram');
END;
BEGIN
p;

END;
Output:
Local subprogram
COMPILING SUBPROGRAMS
6 SQL> Alter procedure P1 compile;
6 SQL> Alter function F1 compile;
SUBPROGRAMS DEPENDECIES
8 A stored subprogram is marked as invalid
in the data dictionary if it has compile
errors.
8 A stored subprogram can also become
invalid if a DDL operation is performed on
one of its dependent objects.
8 If a subprogram is invalidated, the PL/SQL
engine will automatically attempt to
recompile in the next time it is called.
8 If we have two procedures like P1 and P2
in which P1 depends on P2. If we compile
P2 then P1 is invalidated.

SUBPROGRAMS DEPENDENCIES IN REMOTE
DATABASES
1 We will call remote subprogram using
connect string like P1@ORACLE;
1 If we have two procedures like P1 and P2
in which P1 depends on P2 but P2 was in
remote database. If we compile P2 it will
not invalidate P1 immediately because the
data dictionary does not track remote
dependencies.
1 Instead the validity of remote objects is
checked at runtime. When P1 is called, the
remote data dictionary is queried to
determine the status of P2.
1 P1 and P2 are compared to see it P1 needs
to be recompiled, there are two different
methods of comparision
ü Timestamp Model
ü Signature Model
TIMESTAMP MODEL

Ø This is the default model used by oracle.
Ø With this model, the timestamps of the last
modifications of the two objects
are
compared.
Ø The last_ddl_time field of user_objects
contains the timestamp.
Ø If the base object has a newer timestamp
than the dependent object, the
dependent object will be recompiled.
ISSUES WITH THIS MODEL
1 If the objects are in different time zones,
the comparison is invalid.
1 When P1 is in a client side PL/SQL engine
such as oracle forms, in this case it may not
possible to recompile P1, because the
source for it may not be included with the
forms.
SIGNATURE MODEL

1 When a procedure is created, a signature is
stored in the data dictionary in addition to
the p-code.
1 The signature encodes the types and order
of the parametes.
1 When P1 is compiled the first time, the
signature of P2 is included. Thus, P1 only
needs to recompiled when the signature of
P2 changes.
1 In order to use the signature model, the
parameter REMOTE_DEPENDENCIES_MODE
must be set to SIGNATURE. This is a
parameter in the database initialization file.
THREE WAYS OF SETTING THIS MODE
1 Add the line
REMOTE_DEPENDENCIES_MODE=SIGNATU
RE to the database initialization file. The
next time the database is started, the mode
will be set to SIGNATURE for all sessions.
1 Alter system set

remote_dependencies_mode = signature;
This will affect the entire database (all
sessions) from the time the statement is
issued. You must have the ALTER SYSTEM
privilege to issue this command.
1 Alter session set
remote_dependencies_mode = signature;
This will only affect your session
ISSUES WITH THIS MODEL
2 Signatures don’t get modified if the default
values of formal parameters are
changed.
3 Suppose P2 has a default value for one of
its parameters, and P1 is using this
default value. If the default in the
specification for P2 is changed, P1 will not be
recompiled by default. The old value for
the default parameter will still be used until
P1 is manually recompiled.
2 If P1 is calling a packaged procedure P2,

and a new overloaded version of P2 is
added to the remote package, the signature
is not changed. P1 will still use the old
version(not the new overloaded one) until
P1 is recompiled manually.
FORWARD DECLERATION
Before going to use the procedure in any other
subprogram or other block , you must declare
the prototype of the procedure in declarative
section.
Ex1:
DECLARE
PROCEDURE P1 IS
BEGIN
dbms_output.put_line('From
procedure p1');
p2;
END P1;
PROCEDURE P2 IS
BEGIN

procedure p2');
p3;
END P2;
PROCEDURE P3 IS
BEGIN
procedure p3');
END P3;
BEGIN
p1;
END;
Output:
p2;
*
ERROR at line 5:
ORA-06550: line 5, column 1:
PLS-00313: 'P2' not declared in this
scope
PL/SQL: Statement ignored

PLS-00313: 'P3' not declared in this
scope
PL/SQL: Statement ignored
Ex2:
DECLARE
PROCEDURE P2; -- forward
declaration
PROCEDURE P3;
PROCEDURE P1 IS
BEGIN
procedure p1');
p2;
END P1;
PROCEDURE P2 IS
BEGIN
procedure p2');
p3;

END P2;
PROCEDURE P3 IS
BEGIN
procedure p3');
END P3;
BEGIN
p1;
END;
Output:
From procedure p1
From procedure p2
From procedure p3
PRIVILEGES AND STORED SUBPROGRAMS
EXECUTE PREVILEGE
4 For stored subprograms and packages the
relevant privilege is EXECUTE.

4 If user A had the procedure called
emp_proc then user A grants execute
privilege on procedure to user B with the
following command.
SQL> Grant execute on emp_proc to user
B.
6 Then user B can run the procedure by
issuing
SQL> Exec user A.emp_proc
userA created the following procedure
cursor c is select *from student1;
BEGIN
for v in c loop
insert into student2
values(v.no,v.name,v.marks);
end loop;
END P;
userA granted execute privilege to userB using
SQL> grant execute on p to userB

Then userB executed the procedure
SQL> Exec userA.p
If suppose userB also having student2 table
then which table will populate whether userA’s
or userB’s.
The answer is userA’s student2 table only
because by default the procedure will execute
under the privlige set of its owner.
The above procedure is known as definer’s
procedure.
HOW TO POPULATE USER B’s TABLE
7 Oracle introduces Invoker’s and Definer’s
rights.
7 By default it will use the definer’s rights.
7 An invoker’s rights routine can be created
by using AUTHID clause to populate the
userB’s table.
10 It is valid for stand-alone subprograms,
package specifications, and object type

specifications only.
userA created the following procedure
CREATE OR REPLACE PROCEDURE P
AUTHID CURRENT_USER IS
cursor is select *from student1;
BEGIN
for v in c loop
insert into student2
values(v.no,v.name,v.marks);
end loop;
END P;
Then grant execute privilege on p to userB.
Executing the procedure by userB, which
populates userB’s table.
The above procedure is called invoker’s
procedure.
Instead of current_user of authid clause, if you
use definer then it will be called definer’
procedure.

STORED SUBPROGRAMS AND ROLES
we have two users saketh and sudha in which
saketh has student table and sudha does not.
Sudha is going to create a procedure based on
student table owned by saketh. Before doing
this saketh must grant the permissions on this
table to sudha.
SQL> conn saketh/saketh
SQL> grant all on student to sudha;
then sudha can create procedure
SQL> conn sudha/sudha
cursor c is select *from saketh.student;
BEGIN
for v in c loop
dbms_output.put_line(‘No = ‘ ||
v.no);
end loop;
END P;

here procedure will be created.
If the same privilege was granted through a
role it wont create the procedure.
Examine the following code
SQL> create role saketh_role;
SQL> grant all on student to saketh_role;
SQL> grant saketh_role to sudha;
then conn sudha/sudha
cursor c is select *from saketh.student;
BEGIN
for v in c loop
dbms_output.put_line(‘No = ‘ ||
v.no);
end loop;
END P;
The above code will raise error instead of
creating procedure .

This is because of early binding which PL/SQL
uses by default in which references are
evaluated in compile time but when you are
using a role this will affect immediately.
ISSUES WITH INVOKER’S RIGHTS
1 In an invoker’s rights routine, external
references in SQL statements will be
resolved using the caller’s privilege set.
1 But references in PL/SQL statements are
still resolved under the owner’s privilege
set.
TRIGGERS, VIEWS AND INVOKER’S RIGHTS
1 A database trigger will always be executed
with definer’s rights and will execute under
the privilege set of the schema that owns
the triggering table.
1 This is also true for PL/SQL function that is
called from a view. In this case, the
function will execute under the privilege

set of the view’s owner.
PACKAGES
A package is a container for related objects.
It has specification and body. Each of them is
stored separately in data dictionary.
PACKAGE SYNTAX

Create or replace package <package_name>
is
-- package specification includes
subprograms signatures, cursors and global
or
public variables.
End <package_name>;
Create or replace package body
<package_name> is
-- package body includes body for all the
subprograms declared in the spec, private
Variables and cursors.
Begin
-- initialization section
Exception
-- Exception handling seciton
End <package_name>;
IMPORTANT POINGS ABOUT PACKAGES
1 The first time a packaged subprogram is

called or any reference to a packaged
variable or type is made, the package is
instantiated.
1 Each session will have its own copy of
packaged variables, ensuring that two
sessions executing subprograms in the
same package use different memory
locations.
1 In many cases initialization needs to be run
the first time the package is instantiated
within a session. This can be done by
adding initialization section to the package
body after all the objects.
1 Packages are stored in the data dictionary
and can not be local.
1 Packaged subprograms has an advantage
over stand alone subprogram.
1 When ever any reference to package, the
whole package p-code was stored in shared
pool of SGA.
1 Package may have local subprograms.
1 You can include authid clause inside the

package spec not in the body.
1 The execution section of a package is know
as initialization section.
1 You can have an exception section at the
bottom of a package body.
1 Packages subprograms are not invalidated.
COMPILING PACKAGES
1 SQL> Alter package PKG compile;
1 SQL> Alter package PKG compile
specification;
1 SQL> Alter package PKG compile body;
PACKAGE DEPENDENCIES
1 The package body depends on the some
objects and the package header.
1 The package header does not depend on
the package body, which is an advantage of
packages.

1 We can change the package body with out
changing the header.
PACKAGE RUNTIME STATE
Package runtime state is differ for the following
packages.
1 Serially reusable packages
1 Non serially reusable packages
SERIALLY REUSABLE PACKAGES
To force the oracle to use serially reusable
version then include PRAGMA
SERIALLY_REUSABLE in both package spec and
body, Examine the following package.
CREATE OR REPLACE PACKAGE BODY PKG
IS
pragma serially_reusable;
cursor c is select ename from emp;
PROCEDURE EMP_PROC IS
v_ename emp.ename%type;

v_flag boolean := true;
v_numrows number := 0;
BEGIN
if not c%isopen then
open c;
end if;
while v_flag loop
fetch c into v_ename;
v_numrows := v_numrows + 1;
if v_numrows = 5 then
v_flag := false;
end if;
dbms_output.put_line('Ename =
' || v_ename);
end loop;
END EMP_PROC;
END PKG;
SQL> exec pkg.emp_proc
Ename = SMITH
Ename = ALLEN
Ename = WARD

Ename = JONES
Ename = MARTIN
Ename = SMITH
Ename = ALLEN
Ename = WARD
Ename = JONES
Ename = MARTIN
1 The above package displays the same
output for each execution even though the
cursor is not closed.
1 Because the serially reusable version resets
the state of the cursor each time it was
called.
NON SERIALL Y REUSABLE PACKAGES
This is the default version used by the oracle,
examine the following package.
CREATE OR REPLACE PACKAGE PKG IS

procedure emp_proc;
END PKG;
CREATE OR REPLACE PACKAGE BODY
PKG IS
cursor c is select ename from emp;
PROCEDURE EMP_PROC IS
v_ename emp.ename%type;
v_flag boolean := true;
v_numrows number := 0;
BEGIN
if not c%isopen then
open c;
end if;
while v_flag loop
fetch c into v_ename;
v_numrows := v_numrows +
1;
if v_numrows = 5 then
v_flag := false;
end if;
dbms_output.put_line('Ename

= ' || v_ename);
end loop;
END EMP_PROC;
END PKG;
Ename = SMITH
Ename = ALLEN
Ename = WARD
Ename = JONES
Ename = MARTIN
Ename = BLAKE
Ename = CLARK
Ename = SCOTT
Ename = KING
Ename = TURNER
1 The above package displays the different
output for each execution even though the
cursor is not closed.

1 Because the non-serially reusable version
remains the state of the cursor over
database calls.
DEPENDENCIES OF PACKAGE RUNTIME STATE
Dependencies can exists between package
state and anonymous blocks.
Examine the following program
Create this package in first session
v number := 5;
procedure p;
END PKG;
CREATE OR REPLACE PACKAGE BODY PKG
IS
PROCEDURE P IS
BEGIN
dbms_output.put_line('v = ' || v);
v := 10;
dbms_output.put_line('v = ' || v);

END P;
END PKG;
Connect to second session, run the following
code.
BEGIN
pkg.p;
END;
The above code wil work.
Go back to first session and recreate the
package using create.
Then connect to second session and run the
following code again.
BEGIN
pkg.p;
END;
This above code will not work because of the
following.

1 The anonymous block depends on pkg. This
is compile time dependency.
1 There is also a runtime dependency on the
packaged variables, since each session has
its own copy of packaged variables.
1 Thus when pkg is recompiled the runtime
dependency is followed, which invalidates
the block and raises the oracle error.
1 Runtime dependencies exist only on
package state. This includes variables and
cursors declared in a package.
1 If the package had no global variables, the
second execution of the anonymous block
would have succeeded.
PURITY LEVELS
In general, calls to subprograms are
procedural, they cannot be called from SQL
statements. However, if a stand-alone or
packaged function meets certain restrictions, it
can be called during execution of a SQL
statement.

User-defined functions are called the same way
as built-in functions but it must meet different
restrictions. These restrictions are defined in
terms of purity levels.
There are four types of purity levels.
WNDS -- Writes No Database State
RNDS -- Reads No Database State
WNPS -- Writes No Package State
RNPS -- Reads No Package State
In addition to the preceding restrictions, a
user-defined function must also meet the
following requirements to be called from a SQL
statement.
Ø The function has to be stored in the
database, either stand-alone or as part
of a
package.
Ø The function can take only in parametes.
Ø The formal parameters must use only

database types, not PL/SQL types such
as
boolean or record.
Ø The return type of the function must also
be a database type.
Ø The function must not end the current
transaction with commit or rollback, or
rollback to a savepoint prior to the
function execution.
Ø It also must not issue any alter session or
alter system commands.
RESTRICT_REFERENCES
For packaged functions, however, the
RESTRICT_REFERENCES pragma is required to
specify the purity level of a given function.
Syntax:
PRAGMA
RESTRICT_REFERENCES(subprogram_name or
package_name, WNDS [,WNPS]

[,RNDS] [,RNPS]);
Ex:
function fun1 return varchar;
pragma
restrict_references(fun1,wnds);
pragma
restrict_references(fun2,wnds);
END PKG;
PKG IS
FUNCTION FUN1 return varchar IS
BEGIN
update dept set deptno = 11;
return 'hello';
END FUN1;
FUNCTION FUN2 return varchar
IS
BEGIN
update dept set dname ='aa';

return 'hello';
END FUN2;
END PKG;
The above package body will not created, it will
give the following erros.
PLS-00452: Subprogram 'FUN1' violates its
associated pragma
associated pragma
PKG IS
BEGIN
return 'hello';
END FUN1;
IS
BEGIN
return 'hello';
END FUN2;

END PKG;
Now the package body will be created.
DEFAULT
If there is no RESTRICT_REFERENCES pragma
associated with a given packaged function, it
will not have any purity level asserted.
However, you can change the default purity
level for a package. The DEFAULT keyword is
used instead of the subprogram name in the
pragma.
Ex:
pragma
restrict_references(default,wnds);
END PKG;
PKG IS

BEGIN
return 'hello';
END FUN1;
IS
BEGIN
return 'hello';
END FUN2;
END PKG;
The above package body will not created, it will
give the following erros because the pragma
will apply to all the functions.
associated pragma
associated pragma

PKG IS
BEGIN
return 'hello';
END FUN1;
IS
BEGIN
return 'hello';
END FUN2;
END PKG;
Now the package body will be created.
TRUST
If the TRUST keyword is present, the
restrictions listed in the pragma are not
enforced. Rather, they are trusted to be true.
Ex:

pragma
restrict_references(fun1,wnds,trust);
pragma
restrict_references(fun2,wnds,trust);
END PKG;
PKG IS
BEGIN
return 'hello';
END FUN1;
IS
BEGIN
return 'hello';
END FUN2;

END PKG;
The above package will be created successfully.
IMPORTANT POINTS ABOUT
RESTRICT_REFERENCES
Ø This pragma can appear anywhere in the
package specification, after the
function
declaration.
Ø It can apply to only one function definition.
Ø For overload functions, the pragma applies
to the nearest definition prior to the
Pragma.
Ø This pragma is required only for packages
functions not for stand-alone functions.
Ø The Pragma can be declared only inside the
package specification.
Ø The pragma is checked at compile time, not
runtime.
Ø It is possible to specify without any purity
levels when trust or combination of

default and trust keywords are present.
PINNING IN THE SHARED POOL
The shared pool is the portion of the SGS that
contains, among other things, the p-code of
compiled subprograms as they are run. The
first time a stored a store subprogram is called,
the p-code is loaded from disk into the shared
pool. Once the object is no longer referenced, it
is free to be aged out. Objects are aged out of
the shared pool using an LRU(Least Recently
Used) algorithm.
The DBMS_SHARED_POOL package allows you
to pin objects in the shared pool. When an
object is pinned, it will never be aged out until
you request it, no matter how full the pool gets
or how often the object is accessed. This can
improve performance, as it takes time to reload
a package from disk.
DBMS_SHARED_POOL has four procedures

1 KEEP
1 UNKEEP
1 SIZES
1 ABORTED_REQUEST_THRESHOLD
KEEP
The DBMS_SHARED_POOL.KEEP procedure is
used to pin objects in the pool.
Syntax:
PROCEDURE KEEP(object_name
varchar2,flag char default ‘P’);
Here the flag represents different types of flag
values for different types of objects.
P -- Package, function or procedure
Q -- Sequence
R -- Trigger
C -- SQL Cursor
T -- Object type
JS -- Java source

JC -- Java class
JR -- Java resource
JD -- Java shared data
UNKEEP
UNKEEP is the only way to remove a kept
object from the shared pool, without restarting
the database. Kept objects are never aged out
automatically.
Syntax:
PROCEDURE UNKEEP(object_name
varchar2, flag char default ‘P’);
SIZES
SIZES will echo the contents of the shared pool
to the screen.
Syntax:
PROCEDURE SIZES(minsize number);
Objects with greater than the minsize will be
returned. SIZES uses DBMS_OUTPUT to return

the data.
ABORTED_REQUEST_THRESHOLD
When the database determines that there is not
enough memory in the shared pool to satisfy a
given request, it will begin aging objects out
until there is enough memory. It enough
objects are aged out, this can have a
performance impact on other database
sessions. The ABORTED_REQUEST_THRESHOLD
can be used to remedy this.
Syntax:
PROCEDURE
ABORTED_REQUEST_THRESHOLD(threshold_si
ze number);
Once this procedure is called, oracle will not
start aging objects from the pool unless at least
threshold_size bytes is needed.
DATA MODEL FOR SUBPROGRAMS AND
PACKAGES

1 USER_OBJECTS
1 USER_SOURCE
1 USER_ERRORS
1 DBA_OBJECTS
1 DBA_SOURCE
1 DBA_ERRORS
1 ALL_OBJECTS
1 ALL_SOURCE
1 ALL_ERRORS

CURSORS
Cursor is a pointer to memory location which is
called as context area which contains the
information necessary for processing, including
the number of rows processed by the
statement, a pointer to the parsed
representation of the statement, and the active
set which is the set of rows returned by the
query.
Cursor contains two parts
ü Header
ü Body
Header includes cursor name, any parameters
and the type of data being loaded.
Body includes the select statement.
Ex:
Cursor c(dno in number) return dept
%rowtype is select *from dept;

In the above
Header – cursor c(dno in number) return
dept%rowtype
Body – select *from dept
CURSOR TYPES
1 Implicit (SQL)
1 Explicit
ü Parameterized cursors
ü REF cursors
CURSOR STAGES
1 Open
1 Fetch
1 Close
CURSOR ATTRIBUTES
1 %found
1 %notfound
1 %rowcount

1 %isopen
1 %bulk_rowcount
1 %bulk_exceptions
CURSOR DECLERATION
Syntax:
Cursor <cursor_name> is select statement;
Ex:
Cursor c is select *from dept;
CURSOR LOOPS
1 Simple loop
1 While loop
1 For loop
SIMPLE LOOP
Syntax:
Loop
Fetch <cursor_name> into
<record_variable>;

Exit when <cursor_name> %
notfound;
<statements>;
End loop;
Ex:
DECLARE
cursor c is select * from student;
v_stud student%rowtype;
BEGIN
open c;
loop
fetch c into v_stud;
exit when c%notfound;
dbms_output.put_line('Name = ' ||
v_stud.name);
end loop;
close c;
END;
Output:
Name = saketh
Name = srinu

Name = satish
Name = sudha
WHILE LOOP
Syntax:
While <cursor_name> % found loop
Fetch <cursor_name> nto
<record_variable>;
<statements>;
End loop;
Ex:
DECLARE
v_stud student%rowtype;
BEGIN
open c;
while c%found loop
v_stud.name);

end loop;
close c;
END;
Output:
Name = saketh
Name = srinu
Name = satish
Name = sudha
FOR LOOP
Syntax:
for <record_variable> in <cursor_name>
loop
<statements>;
End loop;
Ex:
DECLARE
BEGIN
for v_stud in c loop

v_stud.name);
end loop;
END;
Output:
Name = saketh
Name = srinu
Name = satish
Name = sudha
PARAMETARIZED CURSORS
1 This was used when you are going to use
the cursor in more than one place with
different values for the same where clause.
1 Cursor parameters must be in mode.
1 Cursor parameters may have default
values.
1 The scope of cursor parameter is within the

select statement.
Ex:
DECLARE
cursor c(dno in number) is select * from
dept where deptno = dno;
v_dept dept%rowtype;
BEGIN
open c(20);
loop
fetch c into v_dept;
dbms_output.put_line('Dname = ' ||
v_dept.dname || ' Loc = ' || v_dept.loc);
end loop;
close c;
END;
Output:
Dname = RESEARCH Loc = DALLAS
PACKAGED CURSORS WITH HEADER IN SPEC

AND BODY IN PACKAGE BODY
1 cursors declared in packages will not close
automatically.
1 In packaged cursors you can modify the
select statement without making any
changes to the cursor header in the
package specification.
1 Packaged cursors with must be defined in
the package body itself, and then use it as
global for the package.
1 You can not define the packaged cursor in
any subprograms.
1 Cursor declaration in package with out
body needs the return clause.
Ex1:
cursor c return dept%rowtype is
select * from dept;
procedure proc is
END PKG;

CREATE OR REPLACE PAKCAGE BODY
PKG IS
select * from dept;
PROCEDURE PROC IS
BEGIN
for v in c loop
dbms_output.put_line('Deptno =
' || v.deptno || ' Dname = ' ||
v.
dname || ' Loc = ' || v.loc);
end loop;
END PROC;
END PKG;
Output:
SQL> exec pkg.proc
Deptno = 10 Dname =
ACCOUNTING Loc = NEW YORK
Deptno = 20 Dname = RESEARCH
Loc = DALLAS
Deptno = 30 Dname = SALES Loc

= CHICAGO
Deptno = 40 Dname =
OPERATIONS Loc = BOSTON
Ex2:
CREATE OR REPLACE PAKCAGE BODY
PKG IS
select * from dept where deptno > 20;
PROCEDURE PROC IS
BEGIN
for v in c loop
dbms_output.put_line('Deptno =
' || v.deptno || ' Dname = ' ||
v.dname || '
Loc = ' || v.loc);
end loop;
END PROC;
END PKG;
Output:
SQL> exec pkg.proc

Deptno = 30 Dname = SALES Loc
= CHICAGO
Deptno = 40 Dname =
OPERATIONS Loc = BOSTON
REF CURSORS AND CURSOR VARIABLES
1 This is unconstrained cursor which will
return different types depends upon the
user input.
1 Ref cursors can not be closed implicitly.
1 Ref cursor with return type is called strong
cursor.
1 Ref cursor with out return type is called
weak cursor.
1 You can declare ref cursor type in package
spec as well as body.
1 You can declare ref cursor types in local
subprograms or anonymous blocks.
1 Cursor variables can be assigned from one
to another.

1 You can declare a cursor variable in one
scope and assign another cursor variable
with different scope, then you can use the
cursor variable even though the assigned
cursor variable goes out of scope.
1 Cursor variables can be passed as a
parameters to the subprograms.
1 Cursor variables modes are in or out or in
out.
1 Cursor variables can not be declared in
package spec and package body (excluding
subprograms).
1 You can not user remote procedure calls to
pass cursor variables from one server to
another.
1 Cursor variables can not use for update
clause.
1 You can not assign nulls to cursor
variables.
1 You can not compare cursor variables for
equality, inequality and nullity.

Ex:
REF_CURSOR(TABLE_NAME IN VARCHAR) IS
type t is ref cursor;
c t;
v_dept dept%rowtype;
type r is record(ename emp.ename
%type,job emp.job%type,sal emp.sal
%type);
v_emp r;
v_stud student.name%type;
BEGIN
if table_name = 'DEPT' then
open c for select * from dept;
elsif table_name = 'EMP' then
open c for select ename,job,sal from
emp;
elsif table_name = 'STUDENT' then
open c for select name from student;
end if;
loop
if table_name = 'DEPT' then

fetch c into v_dept;
dbms_output.put_line('Deptno = ' ||
v_dept.deptno || ' Dname = ' ||
v_dept.dna
me || ' Loc = ' || v_dept.loc);
elsif table_name = 'EMP' then
fetch c into v_emp;
dbms_output.put_line('Ename = ' ||
v_emp.ename || ' Job = ' || v_emp.job
|| ' Sal = ' ||
v_emp.sal);
elsif table_name = 'STUDENT' then
v_stud);
end if;
end loop;
close c;
END;

Output:
SQL> exec ref_cursor('DEPT')
Deptno = 10 Dname = ACCOUNTING
Loc = NEW YORK
Deptno = 20 Dname = RESEARCH Loc =
DALLAS
Deptno = 30 Dname = SALES Loc =
CHICAGO
Deptno = 40 Dname = OPERATIONS
Loc = BOSTON
SQL> exec ref_cursor('EMP')
Ename = SMITH Job = CLERK Sal = 800
Ename = ALLEN Job = SALESMAN Sal =
1600
Ename = WARD Job = SALESMAN Sal =
1250
Ename = JONES Job = MANAGER Sal =
2975
Ename = MARTIN Job = SALESMAN Sal

= 1250
Ename = BLAKE Job = MANAGER Sal =
2850
Ename = CLARK Job = MANAGER Sal =
2450
Ename = SCOTT Job = ANALYST Sal =
3000
Ename = KING Job = PRESIDENT Sal =
5000
Ename = TURNER Job = SALESMAN Sal
= 1500
Ename = ADAMS Job = CLERK Sal =
1100
Ename = JAMES Job = CLERK Sal = 950
Ename = FORD Job = ANALYST Sal =
3000
Ename = MILLER Job = CLERK Sal =
1300
SQL> exec ref_cursor('STUDENT')
Name = saketh
Name = srinu

Name = satish
Name = sudha
CURSOR EXPRESSIONS
1 You can use cursor expressions in explicit
cursors.
1 You can use cursor expressions in dynamic
SQL.
1 You can use cursor expressions in REF
cursor declarations and variables.
1 You can not use cursor expressions in
implicit cursors.
1 Oracle opens the nested cursor defined by
a cursor expression implicitly as soon as it
fetches the data containing the cursor
expression from the parent or outer cursor.
1 Nested cursor closes if you close explicitly.
1 Nested cursor closes whenever the outer or
parent cursor is executed again or closed or
canceled.
1 Nested cursor closes whenever an
exception is raised while fetching data from

a parent cursor.
1 Cursor expressions can not be used when
declaring a view.
1 Cursor expressions can be used as an
argument to table function.
1 You can not perform bind and execute
operations on cursor expressions when
using the cursor expressions in dynamic
SQL.
USING NESTED CURSORS OR CURSOR
EXPRESSIONS
Ex:
DECLARE
cursor c is select ename,cursor(select
dname from dept d where e.empno =
d.deptno) from emp e;
c1 t;
c2 t;
v1 emp.ename%type;
v2 dept.dname%type;

BEGIN
open c;
loop
fetch c1 into v1;
exit when c1%notfound;
fetch c2 into v2;
exit when c2%notfound;
dbms_output.put_line('Ename = ' || v1
|| ' Dname = ' || v2);
end loop;
end loop;
close c;
END;
CURSOR CLAUSES
1 Return
1 For update
1 Where current of
1 Bulk collect

RETURN
Cursor c return dept%rowtype is select
*from dept;
Or
Cursor c1 is select *from dept;
Cursor c return c1%rowtype is select *from
dept;
Or
Type t is record(deptno dept.deptno%type,
dname dept.dname%type);
Cursor c return t is select deptno, dname
from dept;
FOR UPDATE AND WHERE CURRENT OF
Normally, a select operation will not take any
locks on the rows being accessed. This will
allow other sessions connected to the database
to change the data being selected. The result
set is still consistent. At open time, when the
active set is determined, oracle takes a
snapshot of the table. Any changes that have

been committed prior to this point are reflected
in the active set. Any changes made after this
point, even if they are committed, are not
reflected unless the cursor is reopened, which
will evaluate the active set again.
However, if the FOR UPDATE caluse is pesent,
exclusive row locks are taken on the rows in
the active set before the open returns. These
locks prevent other sessions from changing the
rows in the active set until the transaction is
committed or rolled back. If another session
already has locks on the rows in the active set,
then SELECT … FOR UPDATE operation will wait
for these locks to be released by the other
session. There is no time-out for this waiting
period. The SELECT…FOR UPDATE will hang
until the other session releases the lock. To
handle this situation, the NOWAIT clause is
available.
Syntax:
Select …from … for update of column_name

[wait n];
If the cursor is declared with the FOR
UPDATE clause, the WHERE CURRENT OF
clause can be used in an update or delete
statement.
Syntax:
Where current of cursor;
Ex:
DECLARE
cursor c is select * from dept for
update of dname;
BEGIN
for v in c loop
update dept set dname = 'aa'
where current of c;
commit;
end loop;
END;
BULK COLLECT

1 This is used for array fetches
1 With this you can retrieve multiple rows of
data with a single roundtrip.
1 This reduces the number of context
switches between the pl/sql and sql
engines.
1 Reduces the overhead of retrieving data.
1 You can use bulk collect in both dynamic
and static sql.
1 You can use bulk collect in select, fetch into
and returning into clauses.
1 SQL engine automatically initializes and
extends the collections you reference in the
bulk collect clause.
1 Bulk collect operation empties the
collection referenced in the into clause
before executing the query.
1 You can use the limit clause of bulk collect
to restrict the no of rows retrieved.
1 You can fetch into multible collections with
one column each.

1 Using the returning clause we can return
data to the another collection.
BULK COLLECT IN FETCH
Ex:
DECLARE
Type t is table of dept%rowtype;
nt t;
BEGIN
Open c;
Fetch c bulk collect into nt;
Close c;
For i in nt.first..nt.last loop
dbms_output.put_line('Dname =
' || nt(i).dname || ' Loc = ' ||
nt(i)
.loc);
end loop;
END;
Output:

Dname = ACCOUNTING Loc = NEW
YORK
Dname = SALES Loc = CHICAGO
Dname = OPERATIONS Loc = BOSTON
BULK COLLECT IN SELECT
Ex:
DECLARE
Nt t;
BEGIN
Select * bulk collect into nt from
dept;
for i in nt.first..nt.last loop
' || nt(i).dname || ' Loc = ' ||
nt(i).loc);
end loop;
END;

Output:
YORK
Dname = SALES Loc = CHICAGO
Dname = OPERATIONS Loc = BOSTON
LIMIT IN BULK COLLECT
You can use this to limit the number of rows to
be fetched.
Ex:
DECLARE
nt t;
BEGIN
Open c;
Fetch c bulk collect into nt limit 2;
Close c;

' || nt(i).dname || ' Loc = ' || nt(i).loc);
end loop;
END;
Output:
YORK
MULTIPLE FETCHES IN INTO CLAUSE
Ex1:
DECLARE
Type t is table of dept.dname
%type;
nt t;
Type t1 is table of dept.loc
%type;
nt1 t;
Cursor c is select dname,loc from
dept;
BEGIN

Open c;
Fetch c bulk collect into nt,nt1;
Close c;
dbms_output.put_line('Dna
me = ' || nt(i));
end loop;
For i in nt1.first..nt1.last loop
dbms_output.put_line('Loc
= ' || nt1(i));
end loop;
END;
Output:
Dname = ACCOUNTING
Dname = RESEARCH
Dname = SALES
Dname = OPERATIONS
Loc = NEW YORK
Loc = DALLAS
Loc = CHICAGO
Loc = BOSTON

Ex2:
DECLARE
type t is table of dept.dname%type;
type t1 is table of dept.loc%type;
nt t;
nt1 t1;
BEGIN
Select dname,loc bulk collect into
nt,nt1 from dept;
for i in nt.first..nt.last loop
' || nt(i));
end loop;
for i in nt1.first..nt1.last loop
dbms_output.put_line('Loc = ' ||
nt1(i));
end loop;
END;
Output:
Dname = ACCOUNTING
Dname = RESEARCH

Dname = SALES
Dname = OPERATIONS
Loc = NEW YORK
Loc = DALLAS
Loc = CHICAGO
Loc = BOSTON
RETURNING CLAUSE IN BULK COLLECT
You can use this to return the processed data
to the ouput variables or typed variables.
Ex:
DECLARE
type t is table of number(2);
nt t := t(1,2,3,4);
type t1 is table of varchar(2);
nt1 t1;
type t2 is table of student
%rowtype;
nt2 t2;
BEGIN
select name bulk collect into nt1

from student;
forall v in nt1.first..nt1.last
update student set no =
nt(v) where name = nt1(v) returning
no,name,marks bulk
collect into nt2;
for v in nt2.first..nt2.last loop
dbms_output.put_line('Marks
= ' || nt2(v));
end loop;
END;
Output:
Marks = 100
Marks = 200
Marks = 300
Marks = 400
POINTS TO REMEMBER
1 Cursor name can be up to 30 characters in
length.
1 Cursors declared in anonymous blocks or

subprograms closes automatically when
that block terminates execution.
1 %bulk_rowcount and %bulk_exceptions
can be used only with forall construct.
1 Cursor declarations may have expressions
with column aliases.
1 These expressions are called virtual
columns or calculated columns.

SQL IN PL/SQL
The only statements allowed directly in pl/sql
are DML and TCL.
BINDING
Binding a variable is the process of identifying
the storage location associated with an

identifier in the program.
Types of binding
1 Early binding
1 Late binding
3 Binding during the compiled phase is early
binding.
3 Binding during the runtime phase is late
binding.
3 In early binding compile phase will take
longer because of binding work but the
Execution is faster.
6 In late binding it will shorten the compile
phase but lengthens the execution time.
6 PL/SQL by default uses early binding.
6 Binding also involves checking the database
for permissions to access the object
Referenced.
DYNAMIC SQL
1 If you use DDL in pl/sql it validates the

permissions and existence if requires
during compile time which makes invalid.
1 We can avoid this by using Dynamic SQL.
1 Dynamic SQL allows you to create a SQL
statement dynamically at runtime.
Two techniques are available for Dynamic
SQL.
1 Native Dynamic SQL
1 DBMS_SQL package
USING NATIVE DYNAMIC SQL
USING EXECUTE IMMEDIATE
Ex:
BEGIN
Execute immediate ‘create table
student(no number(2),name varchar(10))’;
or
Execute immediate (‘create table
student(no number(2),name
varchar(10))’);

END;
USING EXECUTE IMMEDIATE WITH PL/SQL
VARIABLES
Ex:
DECLARE
v varchar(100);
BEGIN
v := 'create table student(no
number(2),name varchar(10))';
execute immediate v;
END;
USING EXECUTE IMMEDIATE WITH BIND
VARIABLES AND USING CLAUSE
Ex:
DECLARE
v varchar(100);
BEGIN
v := 'insert into student
values(:v1,:v2,:v3)';

execute immediate v using 6,'f',600;
END;
EXECUTING QUERIES WITH OPEN FOR AND
USING CLAUSE
Ex:
CREATE OR REPLACE PROCEDURE P(smarks
in number) IS
s varchar(100) := 'select *from student
where marks > :m';
c t;
v student%rowtype;
BEGIN
open c for s using smarks;
loop
fetch c into v;
dbms_output.put_line('Student
Marks = ' || v.marks);
end loop;
close c;

END;
Output:
SQL> exec p(100)
Student Marks = 200
Student Marks = 300
Student Marks = 400
QUERIES WITH EXECUTE IMMEDIATE
Ex:
DECLARE
d_name dept.dname%type;
lc dept.loc%type;
v varchar(100);
BEGIN
v := 'select dname from dept where
deptno = 10';
execute immediate v into d_name;
dbms_output.put_line('Dname = '||
d_name);
v := 'select loc from dept where

dname = :dn';
execute immediate v into lc using
d_name;
dbms_output.put_line('Loc = ' || lc);
END;
Output:
Dname = ACCOUNTING
Loc = NEW YORK
VARIABLE NAMES
Ex:
DECLARE
Marks number(3) := 100;
BEGIN
Delete student where marks = marks;
-- this will delete all the rows in the
-- student table
END;
This can be avoided by using the labeled
blocks.

<<my_block>>
DECLARE
Marks number(3) := 100;
BEGIN
Delete student where marks =
my_block.marks; -- delete rows which
has
-- a marks of 100
END;
GETTING DATA INTO PL/SQL VARIABLES
Ex:
DECLARE
V1 number;
V2 varchar(2);
BEGIN
Select no,name into v1,v2 from student
where marks = 100;
END;

DML AND RECORDS
Ex:
CREATE OR REPLACE PROCEDURE P(srow in
student%rowtype) IS
BEGIN
insert into student values srow;
END P;
DECLARE
s student%rowtype;
BEGIN
s.no := 11;
s.name := 'aa';
s.marks := 100;
p(s);
END;
RECORD BASED INSERTS
Ex:
DECLARE
srow student%rowtype;

BEGIN
srow.no := 7;
srow.name := 'cc';
srow.marks := 500;
insert into student values srow;
END;
RECORD BASED UPDATES
Ex:
DECLARE
BEGIN
srow.no := 6;
srow.name := 'cc';
srow.marks := 500;
update student set row=srow where no
= srow.no;
END;
USING RECORDS WITH RETURNING CLAUSE
Ex:

DECLARE
sreturn student%rowtype;
BEGIN
srow.no := 8;
srow.name := 'dd';
srow.marks := 500;
insert into student values srow
returning no,name,marks into sreturn;
dbms_output.put_line('No = ' ||
sreturn.no);
sreturn.name);
sreturn.marks);
END;
Output:
No = 8
No = dd
No = 500
USING DBMS_SQL PACKAGE

DBMS_SQL is used to execute dynamic SQL
from with in PL/SQL. Unlike native dynamic
SQL, it is not built directly into the language,
and thus is less efficient. The DBMS_SQL
package allows you to directly control the
processing of a statement within a cursor,
with operations such as opening and closing a
cursor, parsing a statement, binding input
variable, and defining output variables.
Ex1:
DECLARE
cursor_id number;
flag number;
v_stmt varchar(50);
BEGIN
cursor_id := dbms_sql.open_cursor;
v_stmt := 'create table stud(sno
number(2),sname varchar(10))';
dbms_sql.parse(cursor_id,v_stmt,dbms
_sql.native);

flag := dbms_sql.execute(cursor_id);
dbms_sql.close_cursor(cursor_id);
dbms_output.put_line('Table created');
END;
Output:
Table created
SQL> desc stud
Name
Null? Type
--------------------------------------------------
--------------- -------- --------
SNO
NUMBER(2)
SNAME
VARCHAR2(10)
Ex2:
DBMS_SQL_PROC(v1 student.no%type,
v2

student.marks%type) is
cursor_id number;
flag number;
v_update varchar(50);
BEGIN
cursor_id := dbms_sql.open_cursor;
v_update := 'update student set marks =
:smarks where no = :sno';
dbms_sql.parse(cursor_id,v_update,dbms_
sql.native);
dbms_sql.bind_variable(cursor_id,':sno',v1
);
dbms_sql.bind_variable(cursor_id,':smarks
',v2);
flag := dbms_sql.execute(cursor_id);
dbms_sql.close_cursor(cursor_id);
END DBMS_SQL_PROC;
Output:
SQL> select * from student; -- before
execution

NO NA MARKS
---- ------ -- ----------
1 a 100
2 b 200
3 c 300
SQL> exec dbms_sql_proc(2,222)
SQL> select * from student; -- after
execution
NO NA MARKS
---- ------ -- ----------
1 a 100
2 b 222
3 c 300
FORALL STATEMENT
This can be used to get the data from the
database at once by reducting the number of
context switches which is a transfer of control
between PL/SQL and SQL engine.

Syntax:
Forall index_var in
[ Lower_bound..upper_bound |
Indices of indexing_collection |
Values of indexing_collection ]
SQL statement;
FORALL WITH NON-SEQUENTIAL ARRAYS
Ex:
DECLARE
type t is table of student.no%type index
by binary_integer;
ibt t;
BEGIN
ibt(1) := 1;
ibt(10) := 2;
forall i in ibt.first..ibt.last
update student set marks = 900
where no = ibt(i);
END;
The above program will give error like

‘element at index [2] does not exists.
You can rectify it in one of the two following
ways.
USGAGE OF INDICES OF TO AVOID THE ABOVE
BEHAVIOUR
This will be used when you have a collection
whose defined rows specify which rows in the
binding array you would like to processed.
Ex:
DECLARE
type t is table of student.no%type
index by binary_integer;
ibt t;
type t1 is table of boolean index by
binary_integer;
ibt1 t1;
BEGIN
ibt(1) := 1;
ibt(10) := 2;
ibt(100) := 3;

ibt1(1) := true;
ibt1(10) := true;
ibt1(100) := true;
forall i in indices of ibt1
where no = ibt(i);
END;
Ouput:
SQL> select * from student -- before
execution
NO NA MARKS
---------- ------------
1 a 100
2 b 200
3 c 300
SQL> select * from student -- after
execution
NO NA MARKS
---------- ------------

1 a 900
2 b 900
3 c 900
USGAGE OF VALUES OF TO AVOID THE ABOVE
BEHAVIOUR
This will be used when you have a collection
of integers whose content identifies the
position in the binding array that you want to
be processed by the FORALL statement.
Ex:
DECLARE
type t is table of student.no%type
index by binary_integer;
ibt t;
type t1 is table of pls_integer index by
binary_integer;
ibt1 t1;
BEGIN
ibt(1) := 1;
ibt(10) := 2;

ibt(100) := 3;
ibt1(11) := 1;
ibt1(15) := 10;
ibt1(18) := 100;
forall i in values of ibt1
where no = ibt(i);
END;
Ouput:
SQL> select * from student -- before
execution
NO NA MARKS
---------- ------------
1 a 100
2 b 200
3 c 300
SQL> select * from student -- after
execution
NO NA MARKS

---------- ------------
1 a 900
2 b 900
3 c 900
POINTS ABOUT BULK BINDS
1 Passing the entire PL/SQL table to the SQL
engine in one step is known as bulk bind.
1 Bulk binds are done using the forall
statement.
1 If there is an error processing one of the
rows in bulk DML operation, only that row
is rolled back.
POINTS ABOUT RETURING CLAUSE
1 This will be used only with DML statements
to return data into PL/SQL variables.
1 This will be useful in situations like , when
performing insert or update or delete if you
want to know the data of the table which
has been effected by the DML.

1 With out going for another SELECT using
RETURNING clause we will get the data
which will avoid a call to RDBMS kernel.
COLLECTIONS
Collections are also composite types, in that
they allow you to treat several variables as a
unit. A collection combines variables of the
same type.
TYPES
1 Varrays
1 Nested tables
1 Index - by tables (Associate arrays)
VARRAYS
A varray is datatype very similar to an array. A

varray has a fixed limit on its size, specified as
part of the declaration. Elements are inserted
into varray starting at index 1, up to maximum
lenth declared in the varray type. The
maximum size of the varray is 2 giga bytes.
Syntax:
Type <type_name> is varray | varying
array (<limit>) of <element_type>;
Ex1:
DECLARE
type t is varray(10) of varchar(2);
va t := t('a','b','c','d');
flag boolean;
BEGIN
dbms_output.put_line('Limit = ' ||
va.limit);
dbms_output.put_line('Count = ' ||
va.count);
dbms_output.put_line('First Index = '
|| va.first);
dbms_output.put_line('Last Index = ' ||

va.last);
dbms_output.put_line('Next Index = '
|| va.next(2));
dbms_output.put_line('Previous Index
= ' || va.prior(3));
dbms_output.put_line('VARRAY
ELEMENTS');
for i in va.first..va.last loop
dbms_output.put_line('va[' || i || ']
= ' || va(i));
end loop;
flag := va.exists(3);
if flag = true then
dbms_output.put_line('Index 3
exists with an element ' || va(3));
else
dbms_output.put_line('Index 3 does
not exists');
end if;
va.extend;
dbms_output.put_line('After extend of
one index, Count = ' || va.count);

if flag = true then
else
not exists');
end if;
if flag = true then
else
not exists');
end if;
va.extend(2);
two indexes, Count = ' || va.count);
ELEMENTS');

= ' || va(i));
end loop;
va(5) := 'e';
va(6) := 'f';
va(7) := 'g';
dbms_output.put_line('AFTER
ASSINGNING VALUES TO EXTENDED
ELEMENTS,
VARR
AY ELEMENTS');
= ' || va(i));
end loop;
va.extend(3,2);
three indexes, Count = ' || va.count);
ELEMENTS');

= ' || va(i));
end loop;
va.trim;
dbms_output.put_line('After trim of
va.trim(3);
three indexs, Count = ' || va.count);
dbms_output.put_line('AFTER TRIM,
VARRAY ELEMENTS');
= ' || va(i));
end loop;
va.delete;
dbms_output.put_line('After delete of
entire varray, Count = ' || va.count);
END;
Output:
Limit = 10
Count = 4

First Index = 1
Last Index = 4
Next Index = 3
Previous Index = 2
VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
Index 3 exists with an element c
After extend of one index, Count = 5
Index 5 exists with an element
Index 6 does not exists
After extend of two indexes, Count = 7
VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] =
va[6] =
va[7] =

AFTER ASSINGNING VALUES TO
EXTENDED ELEMENTS, VARRAY
ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] = e
va[6] = f
va[7] = g
After extend of three indexes, Count =
10
VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] = e
va[6] = f
va[7] = g
va[8] = b
va[9] = b

va[10] = b
After trim of one index, Count = 9
After trim of three indexs, Count = 6
AFTER TRIM, VARRAY ELEMENTS
va[1] = a
va[2] = b
va[3] = c
va[4] = d
va[5] = e
va[6] = f
After delete of entire varray, Count = 0
Ex2:
DECLARE
type t is varray(4) of student
%rowtype;
va t := t(null,null,null,null);
BEGIN
for i in 1..va.count loop
select * into va(i) from student
where sno = i;
dbms_output.put_line('Sno = ' ||

va(i).sno || ' Sname = ' || va(i).sname);
end loop;
END;
Output:
Sno = 1 Sname = saketh
Sno = 2 Sname = srinu
Sno = 3 Sname = divya
Sno = 4 Sname = manogni
Ex3:
DECLARE
type t is varray(4) of student.smarks
%type;
BEGIN
select smarks into va(i) from
student where sno = i;
dbms_output.put_line('Smarks = '
|| va(i));
end loop;
END;

Output:
Smarks = 100
Smarks = 200
Smarks = 300
Smarks = 400
Ex4:
DECLARE
type r is record(c1 student.sname
%type,c2 student.smarks%type);
type t is varray(4) of r;
BEGIN
select sname,smarks into va(i)
from student where sno = i;
dbms_output.put_line('Sname = '
|| va(i).c1 || ' Smarks = ' || va(i).c2);
end loop;
END;
Output:

Sname = saketh Smarks = 100
Sname = srinu Smarks = 200
Sname = divya Smarks = 300
Sname = manogni Smarks = 400
Ex5:
DECLARE
type t is varray(1) of addr;
va t := t(null);
cursor c is select * from employ;
i number := 1;
BEGIN
for v in c loop
select address into va(i) from
employ where ename = v.ename;
dbms_output.put_line('Hno = ' ||
va(i).hno || ' City = ' || va(i).city);
end loop;
END;
Output:
Hno = 11 City = hyd
Hno = 22 City = bang

Hno = 33 City = kochi
Ex6:
DECLARE
va1 t;
va2 t := t();
BEGIN
if va1 is null then
dbms_output.put_line('va1 is null');
else
dbms_output.put_line('va1 is not
null');
end if;
if va2 is null then
dbms_output.put_line('va2 is null');
else
dbms_output.put_line('va2 is not
null');
end if;
END;

Output:
va1 is null
va2 is not null
NESTED TABLES
A nested table is thought of a database table
which has no limit on its size. Elements are
inserted into nested table starting at index 1.
The maximum size of the varray is 2 giga bytes.
Syntax:
Type <type_name> is table of
<table_type>;
Ex1:
DECLARE
type t is table of varchar(2);
nt t := t('a','b','c','d');
flag boolean;
BEGIN
if nt.limit is null then
dbms_output.put_line('No limit to

Nested Tables');
else
nt.limit);
end if;
nt.count);
|| nt.first);
dbms_output.put_line('Last Index = '
|| nt.last);
|| nt.next(2));
= ' || nt.prior(3));
dbms_output.put_line('NESTED TABLE
ELEMENTS');
for i in 1..nt.count loop
dbms_output.put_line('nt[' || i || ']
= ' || nt(i));
end loop;
flag := nt.exists(3);

if flag = true then
exists with an element ' || nt(3));
else
does not exists');
end if;
nt.extend;
one index, Count = ' || nt.count);
if flag = true then
else
not exists');
end if;
if flag = true then

else
not exists');
end if;
nt.extend(2);
two indexes, Count = ' || nt.count);
ELEMENTS');
= ' || nt(i));
end loop;
nt(5) := 'e';
nt(6) := 'f';
nt(7) := 'g';
dbms_output.put_line('AFTER
ASSINGNING VALUES TO EXTENDED
ELEMENTS, NESTED
TABLE
ELEMENTS');

dbms_output.put_line('nt[' || i ||
'] = ' || nt(i));
end loop;
nt.extend(5,2);
five indexes, Count = ' || nt.count);
ELEMENTS');
= ' || nt(i));
end loop;
nt.trim;
nt.trim(3);
three indexs, Count = ' || nt.count);
dbms_output.put_line('AFTER TRIM,
NESTED TABLE ELEMENTS');
dbms_output.put_line('nt[' || i ||

'] = ' || nt(i));
end loop;
nt.delete(1);
first index, Count = ' || nt.count);
ELEMENTS');
for i in 2..nt.count+1 loop
= ' || nt(i));
end loop;
nt.delete(4);
fourth index, Count = ' || nt.count);
ELEMENTS');
for i in 2..3 loop
= ' || nt(i));
end loop;
for i in 5..nt.count+2 loop

= ' || nt(i));
end loop;
nt.delete;
entire nested table, Count = ' ||
nt.count);
END;
Output:
No limit to Nested Tables
Count = 4
First Index = 1
Last Index = 4
Next Index = 3
Previous Index = 2
NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d

Index 5 exists with an element
After extend of two indexes, Count = 7
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] =
nt[6] =
nt[7] =
AFTER ASSINGNING VALUES TO
EXTENDED ELEMENTS, NESTED TABLE
ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
After extend of five indexes, Count =

12
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
nt[9] = b
nt[10] = b
nt[11] = b
nt[12] = b
After trim of three indexs, Count = 8
AFTER TRIM, NESTED TABLE ELEMENTS
nt[1] = a
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e

nt[6] = f
nt[7] = g
nt[8] = b
After delete of first index, Count = 7
nt[2] = b
nt[3] = c
nt[4] = d
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
After delete of fourth index, Count = 6
nt[2] = b
nt[3] = c
nt[5] = e
nt[6] = f
nt[7] = g
nt[8] = b
After delete of entire nested table,
Count = 0

Ex2:
DECLARE
type t is table of student%rowtype;
nt t := t(null,null,null,null);
BEGIN
select * into nt(i) from student
where sno = i;
dbms_output.put_line('Sno = ' ||
nt(i).sno || ' Sname = ' || nt(i).sname);
end loop;
END;
Output:
Sno = 1 Sname = saketh
Sno = 2 Sname = srinu
Sno = 3 Sname = divya
Sno = 4 Sname = manogni
Ex3:
DECLARE
type t is table of student.smarks

%type;
BEGIN
select smarks into nt(i) from
dbms_output.put_line('Smarks = '
|| nt(i));
end loop;
END;
Output:
Smarks = 100
Smarks = 200
Smarks = 300
Smarks = 400
Ex4:
DECLARE
type r is record(c1 student.sname
%type,c2 student.smarks%type);
type t is table of r;

BEGIN
select sname,smarks into nt(i) from
dbms_output.put_line('Sname = '
|| nt(i).c1 || ' Smarks = ' || nt(i).c2);
end loop;
END;
Output:
Sname = saketh Smarks = 100
Sname = srinu Smarks = 200
Sname = divya Smarks = 300
Sname = manogni Smarks = 400
Ex5:
DECLARE
type t is table of addr;
nt t := t(null);
cursor c is select * from employ;
i number := 1;

BEGIN
for v in c loop
select address into nt(i) from
employ where ename = v.ename;
dbms_output.put_line('Hno = ' ||
nt(i).hno || ' City = ' || nt(i).city);
end loop;
END;
Output:
Hno = 11 City = hyd
Hno = 22 City = bang
Hno = 33 City = kochi
Ex6:
DECLARE
nt1 t;
nt2 t := t();
BEGIN
if nt1 is null then
dbms_output.put_line('nt1 is null');
else

dbms_output.put_line('nt1 is not
null');
end if;
if nt2 is null then
dbms_output.put_line('nt2 is null');
else
dbms_output.put_line('nt2 is not
null');
end if;
END;
Output:
nt1 is null
nt2 is not null
SET OPERATIONS IN NESTED TABLES
You can perform set operations in the nested
tables. You can also perform equality
comparisions between nested tables.
Possible operations are

1 UNION
1 UNION DISTINCT
1 INTERSECT
1 EXCEPT ( act like MINUS)
Ex:
DECLARE
type t is table of varchar(2);
nt1 t := t('a','b','c');
nt2 t := t('c','b','a');
nt3 t := t('b','c','a','c');
nt4 t := t('a','b','d');
nt5 t;
BEGIN
nt5 := set(nt1);
ELEMENTS');
dbms_output.put_line('nt5[ ' || i ||
' ] = ' || nt5(i));
end loop;

nt5 := set(nt3);
ELEMENTS');
dbms_output.put_line('nt5[ ' || i || ' ]
= ' || nt5(i));
end loop;
nt5 := nt1 multiset union nt4;
ELEMENTS');
= ' || nt5(i));
end loop;
nt5 := nt1 multiset union nt3;
ELEMENTS');
= ' || nt5(i));
end loop;
nt5 := nt1 multiset union distinct nt3;

ELEMENTS');
= ' || nt5(i));
end loop;
nt5 := nt1 multiset except nt4;
ELEMENTS');
= ' || nt5(i));
end loop;
nt5 := nt4 multiset except nt1;
ELEMENTS');
= ' || nt5(i));
end loop;
END;

Output:
nt5[ 1 ] = a
nt5[ 2 ] = b
nt5[ 3 ] = c
nt5[ 1 ] = b
nt5[ 2 ] = c
nt5[ 3 ] = a
nt5[ 1 ] = a
nt5[ 2 ] = b
nt5[ 3 ] = c
nt5[ 4 ] = a
nt5[ 5 ] = b
nt5[ 6 ] = d
nt5[ 1 ] = a
nt5[ 2 ] = b
nt5[ 3 ] = c
nt5[ 4 ] = b

nt5[ 5 ] = c
nt5[ 6 ] = a
nt5[ 7 ] = c
nt5[ 1 ] = a
nt5[ 2 ] = b
nt5[ 3 ] = c
nt5[ 1 ] = c
nt5[ 1 ] = d
INDEX-BY TABLES
An index-by table has no limit on its size.
Elements are inserted into index-by table
whose index may start non-sequentially
including negative integers.
Syntax:
Type <type_name> is table of
<table_type> index by binary_integer;

Ex:
DECLARE
type t is table of varchar(2) index by
binary_integer;
ibt t;
flag boolean;
BEGIN
ibt(1) := 'a';
ibt(-20) := 'b';
ibt(30) := 'c';
ibt(100) := 'd';
if ibt.limit is null then
Index by Tables');
else
ibt.limit);
end if;
ibt.count);
|| ibt.first);

|| ibt.last);
|| ibt.next(2));
= ' || ibt.prior(3));
dbms_output.put_line('INDEX BY
TABLE ELEMENTS');
dbms_output.put_line('ibt[-20] = ' ||
ibt(-20));
dbms_output.put_line('ibt[1] = ' ||
ibt(1));
ibt(30));
ibt(100));
flag := ibt.exists(30);
if flag = true then
exists with an element ' || ibt(30));
else

does not exists');
end if;
if flag = true then
exists with an element ' || ibt(30));
else
does not exists');
end if;
ibt.delete(1);
first index, Count = ' || ibt.count);
ibt.delete(30);
index thirty, Count = ' || ibt.count);
dbms_output.put_line('INDEX BY
TABLE ELEMENTS');
dbms_output.put_line('ibt[-20] = ' ||
ibt(-20));
ibt(100));

ibt.delete;
entire index-by table, Count = ' ||
ibt.count);
END;
Output:
No limit to Index by Tables
Count = 4
First Index = -20
Last Index = 100
Next Index = 30
Previous Index = 1
INDEX BY TABLE ELEMENTS
ibt[-20] = b
ibt[1] = a
ibt[30] = c
ibt[100] = d
After delete of index thirty, Count = 2

INDEX BY TABLE ELEMENTS
ibt[-20] = b
ibt[100] = d
After delete of entire index-by table,
Count = 0
DIFFERENCES AMONG COLLECTIONS
1 Varrays has limit, nested tables and index-
by tables has no limit.
1 Varrays and nested tables must be
initialized before assignment of elements,
in index-by tables we can directly assign
elements.
1 Varrays and nested tables stored in
database, but index-by tables can not.
1 Nested tables and index-by tables are
PL/SQL tables, but varrays can not.
1 Keys must be positive in case of nested
tables and varrays, in case of index-by
tables keys can be positive or negative.
1 Referencing nonexistent elements raises
SUBSCRIPT_BEYOND_COUNT in both

nested tables and varrays, but in case of
index-by tables NO_DATA_FOUND raises.
1 Keys are sequential in both nested tables
and varrays, non-sequential in index-by
tables.
1 Individual indexes can be deleted in both
nested tables and index-by tables, but in
varrays can not.
1 Individual indexes can be trimmed in both
nested tables and varrays, but in index-by
tables can not.
1 Individual indexes can be extended in both
nested tables and varrays, but in index-by
tables can not.
MULTILEVEL COLLECTIONS
Collections of more than one dimension which
is a collection of collections, known as
multilevel collections.
Syntax:
Type <type_name1> is table of

<table_type> index by binary_integer;
Type <type_name2> is varray(<limit>) |
table | of <type_name1> | index by
binary_integer;
Ex1:
DECLARE
type t1 is table of varchar(2) index by
binary_integer;
type t2 is varray(5) of t1;
va t2 := t2();
c number := 97;
flag boolean;
BEGIN
va.extend(4);
va.count);
va.limit);
for j in 1..va.count loop
va(i)(j) := chr(c);

c := c + 1;
end loop;
end loop;
ELEMENTS');
dbms_output.put_line('va[' || i
|| '][' || j || '] = ' || va(i)(j));
end loop;
end loop;
dbms_output.put_line('First index = '
|| va.first);
dbms_output.put_line('Last index = '
|| va.last);
dbms_output.put_line('Next index = '
|| va.next(2));
dbms_output.put_line('Previous index
= ' || va.prior(3));
if flag = true then

exists');
else
exists');
end if;
va.extend;
va(1)(5) := 'q';
va(2)(5) := 'r';
va(3)(5) := 's';
va(4)(5) := 't';
va(5)(1) := 'u';
va(5)(2) := 'v';
va(5)(3) := 'w';
va(5)(4) := 'x';
va(5)(5) := 'y';
ELEMENTS');

|| '][' || j || '] = ' || va(i)(j));
end loop;
end loop;
va.trim;
va.trim(2);
two indexes, Count = ' || va.count);
ELEMENTS');
|| '][' || j || '] = ' || va(i)(j));
end loop;
end loop;
va.delete;
entire varray, Count = ' || va.count);
END;

Output:
Count = 4
Limit = 5
VARRAY ELEMENTS
va[1][1] = a
va[1][2] = b
va[1][3] = c
va[1][4] = d
va[2][1] = e
va[2][2] = f
va[2][3] = g
va[2][4] = h
va[3][1] = i
va[3][2] = j
va[3][3] = k
va[3][4] = l
va[4][1] = m
va[4][2] = n
va[4][3] = o
va[4][4] = p
First index = 1

Last index = 4
Next index = 3
Previous index = 2
Index 2 exists
VARRAY ELEMENTS
va[1][1] = a
va[1][2] = b
va[1][3] = c
va[1][4] = d
va[1][5] = q
va[2][1] = e
va[2][2] = f
va[2][3] = g
va[2][4] = h
va[2][5] = r
va[3][1] = i
va[3][2] = j
va[3][3] = k
va[3][4] = l
va[3][5] = s
va[4][1] = m

va[4][2] = n
va[4][3] = o
va[4][4] = p
va[4][5] = t
va[5][1] = u
va[5][2] = v
va[5][3] = w
va[5][4] = x
va[5][5] = y
After trim of two indexes, Count = 2
VARRAY ELEMENTS
va[1][1] = a
va[1][2] = b
va[2][1] = e
va[2][2] = f
After delete of entire varray, Count = 0
Ex2:
DECLARE
binary_integer;

type t2 is table of t1;
nt t2 := t2();
c number := 65;
v number := 1;
flag boolean;
BEGIN
nt.extend(4);
nt.count);
if nt.limit is null then
Nested Tables');
else
nt.limit);
end if;
for j in 1..nt.count loop
nt(i)(j) := chr(c);
c := c + 1;
if c = 91 then
c := 97;

end if;
end loop;
end loop;
ELEMENTS');
dbms_output.put_line('nt[' || i
|| '][' || j || '] = ' || nt(i)(j));
end loop;
end loop;
dbms_output.put_line('First index = '
|| nt.first);
dbms_output.put_line('Last index = '
|| nt.last);
dbms_output.put_line('Next index = '
|| nt.next(2));
dbms_output.put_line('Previous index
= ' || nt.prior(3));
if flag = true then

exists');
else
exists');
end if;
nt.extend(2);
nt(1)(5) := 'Q';
nt(1)(6) := 'R';
nt(2)(5) := 'S';
nt(2)(6) := 'T';
nt(3)(5) := 'U';
nt(3)(6) := 'V';
nt(4)(5) := 'W';
nt(4)(6) := 'X';
nt(5)(1) := 'Y';
nt(5)(2) := 'Z';
nt(5)(3) := 'a';
nt(5)(4) := 'b';
nt(5)(5) := 'c';
nt(5)(6) := 'd';
nt(6)(1) := 'e';
nt(6)(2) := 'f';

nt(6)(3) := 'g';
nt(6)(4) := 'h';
nt(6)(5) := 'i';
nt(6)(6) := 'j';
ELEMENTS');
|| '][' || j || '] = ' || nt(i)(j));
end loop;
end loop;
nt.trim;
one indexe, Count = ' || nt.count);
nt.trim(2);
two indexes, Count = ' || nt.count);
ELEMENTS');

|| '][' || j || '] = ' || nt(i)(j));
end loop;
end loop;
nt.delete(2);
second index, Count = ' || nt.count);
ELEMENTS');
loop
exit when v = 4;
for j in 1..nt.count+1 loop
dbms_output.put_line('nt[' || v
|| '][' || j || '] = ' || nt(v)(j));
end loop;
v := v + 1;
if v= 2 then
v := 3;
end if;
end loop;

nt.delete;
entire nested table, Count = ' ||
nt.count);
END;
Output:
Count = 4
No limit to Nested Tables
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[1][4] = D
nt[2][1] = E
nt[2][2] = F
nt[2][3] = G
nt[2][4] = H
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K

nt[3][4] = L
nt[4][1] = M
nt[4][2] = N
nt[4][3] = O
nt[4][4] = P
First index = 1
Last index = 4
Next index = 3
Previous index = 2
Index 2 exists
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[1][4] = D
nt[1][5] = Q
nt[1][6] = R
nt[2][1] = E
nt[2][2] = F
nt[2][3] = G
nt[2][4] = H

nt[2][5] = S
nt[2][6] = T
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K
nt[3][4] = L
nt[3][5] = U
nt[3][6] = V
nt[4][1] = M
nt[4][2] = N
nt[4][3] = O
nt[4][4] = P
nt[4][5] = W
nt[4][6] = X
nt[5][1] = Y
nt[5][2] = Z
nt[5][3] = a
nt[5][4] = b
nt[5][5] = c
nt[5][6] = d
nt[6][1] = e
nt[6][2] = f

nt[6][3] = g
nt[6][4] = h
nt[6][5] = i
nt[6][6] = j
After trim of one indexe, Count = 5
After trim of two indexes, Count = 3
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[2][1] = E
nt[2][2] = F
nt[2][3] = G
nt[3][1] = I
nt[3][2] = J
nt[3][3] = K
After delete of second index, Count = 2
nt[1][1] = A
nt[1][2] = B
nt[1][3] = C
nt[3][1] = I

nt[3][2] = J
nt[3][3] = K
After delete of entire nested table,
Count = 0
Ex3:
DECLARE
binary_integer;
type t2 is table of t1 index by
binary_integer;
ibt t2;
flag boolean;
BEGIN
ibt.count);
if ibt.limit is null then
Index-by Tables');
else
ibt.limit);

end if;
ibt(1)(1) := 'a';
ibt(4)(5) := 'b';
ibt(5)(1) := 'c';
ibt(6)(2) := 'd';
ibt(8)(3) := 'e';
ibt(3)(4) := 'f';
dbms_output.put_line('INDEX-BY
TABLE ELEMENTS');
dbms_output.put_line('ibt([1][1] = ' ||
ibt(1)(1));
ibt(4)(5));
ibt(5)(1));
ibt(6)(2));
ibt(8)(3));
ibt(3)(4));

|| ibt.first);
|| ibt.last);
|| ibt.next(3));
dbms_output.put_line('Prior Index = '
|| ibt.prior(8));
ibt(1)(2) := 'g';
ibt(1)(3) := 'h';
ibt(1)(4) := 'i';
ibt(1)(5) := 'k';
ibt(1)(6) := 'l';
ibt(1)(7) := 'm';
ibt(1)(8) := 'n';
ibt.count);
TABLE ELEMENTS');
for i in 1..8 loop
dbms_output.put_line('ibt[1][' || i
|| '] = ' || ibt(1)(i));
end loop;

ibt(4)(5));
ibt(5)(1));
ibt(6)(2));
ibt(8)(3));
ibt(3)(4));
if flag = true then
exists');
else
exists');
end if;
ibt.delete(1);
first index, Count = ' || ibt.count);
ibt.delete(4);

fourth index, Count = ' || ibt.count);
TABLE ELEMENTS');
ibt(5)(1));
ibt(6)(2));
ibt(8)(3));
ibt(3)(4));
ibt.delete;
entire index-by table, Count = ' ||
ibt.count);
END;
Output:
Count = 0
No limit to Index-by Tables
INDEX-BY TABLE ELEMENTS

ibt([1][1] = a
ibt([4][5] = b
ibt([5][1] = c
ibt([6][2] = d
ibt([8][3] = e
ibt([3][4] = f
First Index = 1
Last Index = 8
Next Index = 4
Prior Index = 6
Count = 6
ibt[1][1] = a
ibt[1][2] = g
ibt[1][3] = h
ibt[1][4] = i
ibt[1][5] = k
ibt[1][6] = l
ibt[1][7] = m
ibt[1][8] = n
ibt([4][5] = b
ibt([5][1] = c

ibt([6][2] = d
ibt([8][3] = e
ibt([3][4] = f
Index 3 exists
After delete of fourth index, Count = 4
ibt([5][1] = c
ibt([6][2] = d
ibt([8][3] = e
ibt([3][4] = f
After delete of entire index-by table,
Count = 0
Ex4:
DECLARE
binary_integer;
type t2 is table of t1 index by
binary_integer;
type t3 is table of t2;
nt t3 := t3();

c number := 65;
BEGIN
nt.extend(2);
nt.count);
for k in 1..nt.count loop
nt(i)(j)(k) := chr(c);
c := c + 1;
end loop;
end loop;
end loop;
ELEMENTS');
for k in 1..nt.count loop
dbms_output.put_line('nt['
|| i || '][' || j || '][' || k || '] = ' ||
nt(i)(j)(k));

end loop;
end loop;
end loop;
END;
Output:
Count = 2
nt[1][1][1] = A
nt[1][1][2] = B
nt[1][2][1] = C
nt[1][2][2] = D
nt[2][1][1] = E
nt[2][1][2] = F
nt[2][2][1] = G
nt[2][2][2] = H
OBJECTS USED IN THE EXAMPLES
SNO SNAME SMARKS
---------- -------------- ----------

1 saketh 100
2 srinu 200
3 divya 300
4 manogni 400
SQL> create or replace type addr as
object(hno number(2),city
varchar(10));/
SQL> select * from employ;
ENAME JOB ADDRESS(HNO,
CITY)
---------- ----------
-----------------------------
Ranjit clerk ADDR(11, 'hyd')
Satish manager ADDR(22, 'bang')
Srinu engineer ADDR(33, 'kochi')

ERROR HANDLING
PL/SQL implements error handling with
exceptions and exception handlers. Exceptions
can be associated with oracle errors or with
your own user-defined errors. By using

exceptions and exception handlers, you can
make your PL/SQL programs robust and able to
deal with both unexpected and expected errors
during execution.
ERROR TYPES
1 Compile-time errors
1 Runtime errors
Errors that occur during the compilation phase
are detected by the PL/SQL engine and
reported back to the user, we have to correct
them.
Runtime errors are detected by the PL/SQL
runtime engine which can programmatically
raise and caught by exception handlers.
Exceptions are designed for run-time error
handling, rather than compile-time error
handling.
HANDLING EXCEPTIONS
When exception is raised, control passes to the

exception section of the block. The exception
section consists of handlers for some or all of
the exceptions. An exception handler contains
the code that is executed when the error
associated with the exception occurs, and the
exception is raised.
Syntax:
EXCEPTION
When exception_name then
Sequence_of_statements;
When exception_name then
When others then
END;
EXCEPTION TYPES
3 Predefined exceptions
3 User-defined exceptions
PREDEFINED EXCEPTIONS

Oracle has predefined several exceptions that
corresponds to the most common oracle errors.
Like the predefined types, the identifiers of
these exceptions are defined in the STANDARD
package. Because of this, they are already
available to the program, it is not necessary to
declare them in the declarative secion.
Ex1:
DECLARE
a number;
b varchar(2);
v_marks number;
va t := t('a','b');
va1 t;
BEGIN
-- NO_DATA_FOUND
BEGIN
select smarks into v_marks from
student where sno = 50;

EXCEPTION
when no_data_found then
dbms_output.put_line('In
valid student number');
END;
-- CURSOR_ALREADY_OPEN
BEGIN
open c;
open c;
EXCEPTION
when cursor_already_open then
dbms_output.put_line('Cu
rsor is already opened');
END;
-- INVALID_CURSOR
BEGIN
close c;
open c;
close c;
close c;
EXCEPTION

when invalid_cursor then
dbms_output.put_line('Cu
rsor is already closed');
END;
-- TOO_MANY_ROWS
BEGIN
select smarks into v_marks
from student where sno > 1;
EXCEPTION
when too_many_rows then
dbms_output.put_line('To
o many values are coming to marks
v
ariable');
END;
-- ZERO_DIVIDE
BEGIN
a := 5/0;
EXCEPTION
when zero_divide then
dbms_output.put_line('D
ivided by zero - invalid operation');

END;
-- VALUE_ERROR
BEGIN
b := 'saketh';
EXCEPTION
when value_error then
dbms_output.put_line('I
nvalid string length');
END;
-- INVALID_NUMBER
BEGIN
insert into student
values('a','srinu',100);
EXCEPTION
when invalid_number then
nvalid number');
END;
-- SUBSCRIPT_OUTSIDE_LIMIT
BEGIN
va(4) := 'c';

EXCEPTION
when subscript_outside_limit
then
ndex is greater than the limit');
END;
-- SUBSCRIPT_BEYOND_COUNT
BEGIN
va(3) := 'c';
EXCEPTION
when subscript_beyond_count
then
ndex is greater than the count');
END;
-- COLLECTION_IS_NULL
BEGIN
va1(1) := 'a';
EXCEPTION
when collection_is_null then
dbms_output.put_line('C
ollection is empty');

END;
--
END;
Output:
Invalid student number
Cursor is already opened
Cursor is already closed
Too many values are coming to marks
variable
Divided by zero - invalid operation
Invalid string length
Invalid number
Index is greater than the limit
Index is greater than the count
Collection is empty
Ex2:
DECLARE
c number;
BEGIN

c := 5/0;
EXCEPTION
dbms_output.put_line('Inva
lid Operation');
when others then
dbms_output.put_line('Fro
m OTHERS handler: Invalid
O
peration');
END;
Output:
Invalid Operation
USER-DEFINED EXCEPTIONS
A user-defined exception is an error that is
defined by the programmer. User-defined
exceptions are declared in the declarative
secion of a PL/SQL block. Just like variables,
exeptions have a type EXCEPTION and scope.

RAISING EXCEPTIONS
User-defined exceptions are raised explicitly
via the RAISE statement.
Ex:
DECLARE
e exception;
BEGIN
raise e;
EXCEPTION
when e then
dbms_output.put_line('e is
raised');
END;
Output:
e is raised
BULIT-IN ERROR FUNCTIONS
SQLCODE AND SQLERRM
1 SQLCODE returns the current error code,
and SQLERRM returns the current error

message text;
1 For user-defined exception SQLCODE
returns 1 and SQLERRM returns “user-
deifned exception”.
1 SQLERRM wiil take only negative value
except 100. If any positive value other than
100 returns non-oracle exception.
Ex1:
DECLARE
e exception;
v_dname varchar(10);
BEGIN
-- USER-DEFINED EXCEPTION
BEGIN
raise e;
EXCEPTION
when e then
dbms_output.put_line(S
QLCODE || ' ' || SQLERRM);
END;
-- PREDEFINED EXCEPTION

BEGIN
select dname into v_dname
from dept where deptno = 50;
EXCEPTION
when no_data_found then
dbms_output.put_line(S
QLCODE || ' ' || SQLERRM);
END;
END;
Output:
1 User-Defined Exception
100 ORA-01403: no data found
Ex2:
BEGIN
dbms_output.put_line(SQLERRM(1
00));
));
));

dbms_output.put_line(SQLERRM(-
100));
500));
00));
900));
END;
Output:
ORA-01403: no data found
ORA-0000: normal, successful
completion
User-Defined Exception
ORA-00100: no data found
ORA-00500: Message 500 not found;
product=RDBMS; facility=ORA
-200: non-ORACLE exception
ORA-00900: invalid SQL statement
DBMS_UTILITY.FORMAT_ERROR_STACK
1 The built-in function, like SQLERRM,

returns the message associated with the
current error.
1 It differs from SQLERRM in two ways:
1 Its length is not restricted; it will return the
full error message string.
1 You can not pass an error code number to
this function; it cannot be used to return
the message for a random error code.
Ex:
DECLARE
v number := 'ab';
BEGIN
null;
EXCEPTION
when others then
dbms_output.put_line(dbms_
utility.format_error_stack);
END;
Output:
declare
*

ERROR at line 1:
ORA-06502: PL/SQL: numeric or value
error: character to number conversion
error
ORA-06512: at line 2
DBMS_UTILITY.FORMAT_CALL_STACK
This function returns a formatted string
showing the execution call stack inside your
PL/SQL application. Its usefulness is not
restricted to error management; you will also
find its handy for tracing the exectution of your
code. You may not use this function in
exception block.
Ex:
BEGIN
dbms_output.put_line(dbms_utility.
format_call_stack);
END;
Output:

----- PL/SQL Call Stack -----
Object_handle line_number
object_name
69760478 2
anonymous block
DBMS_UTILITY.FORMAT_ERROR_BACKTRACE
It displays the execution stack at the point
where an exception was raised. Thus , you can
call this function with an exception section at
the top level of your stack and still find out
where the error was raised deep within the call
stack.
Ex:
CREATE OR REPLACE PROCEDURE P1 IS
BEGIN
dbms_output.put_line('from
procedure 1');
raise value_error;
END P1;

BEGIN
procedure 2');
p1;
END P2;
BEGIN
procedure 3');
p2;
EXCEPTION
when others then
dbms_output.put_line(dbms_
utility.format_error_backtrace);
END P3;
Output:
SQL> exec p3
from procedure 3
from procedure 2
from procedure 1

ORA-06512: at "SAKETH.P1", line 4
EXCEPTION_INIT PRAGMA
Using this you can associate a named exception
with a particular oracle error. This gives you
the ability to trap this error specifically, rather
than via an OTHERS handler.
Syntax:
PRAGMA
EXCEPTION_INIT(exception_name,
oracle_error_number);
Ex:
DECLARE
e exception;
pragma exception_init(e,-1476);
c number;
BEGIN
c := 5/0;
EXCEPTION

when e then
dbms_output.put_line('Inval
id Operation');
END;
Output:
Invalid Operation
RAISE_APPLICATION_ERROR
You can use this built-in function to create your
own error messages, which can be more
descriptive than named exceptions.
Syntax:
RAISE_APPLICATION_ERROR(error_number,
error_message,, [keep_errors_flag]);
The Boolean parameter keep_errors_flag is
optional. If it is TRUE, the new error is added to
the list of errors already raised. If it is FALSE,
which is default, the new error will replace the
current list of errors.

Ex:
DECLARE
c number;
BEGIN
c := 5/0;
EXCEPTION
raise_application_error(-
20222,'Invalid Operation');
END;
Output:
DECLARE
*
ERROR at line 1:
ORA-20222: Invalid Operation
EXCEPTION PROPAGATION
Exceptions can occur in the declarative, the
executable, or the exception section of a

PL/SQL block.
EXCEPTION RAISED IN THE EXECUATABLE
SECTION
Exceptions raised in execuatable section can be
handled in current block or outer block.
Ex1:
DECLARE
e exception;
BEGIN
BEGIN
raise e;
END;
EXCEPTION
when e then
raised');
END;
Output:
e is raised

Ex2:
DECLARE
e exception;
BEGIN
BEGIN
raise e;
END;
END;
Output:
ERROR at line 1:
ORA-06510: PL/SQL: unhandled user-
defined exception
EXCEPTION RAISED IN THE DECLARATIVE
SECTION
Exceptions raised in the declarative secion
must be handled in the outer block.
Ex1:
DECLARE

c number(3) := 'abcd';
BEGIN
dbms_output.put_line('Hello');
EXCEPTION
when others then
dbms_output.put_line('Invali
d string length');
END;
Output:
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value
error: character to number conversion
error
Ex2:
BEGIN
DECLARE
c number(3) := 'abcd';
BEGIN
dbms_output.put_line('Hello');
EXCEPTION

when others then
dbms_output.put_line('Inv
alid string length');
END;
EXCEPTION
when others then
outer block: Invalid string length');
END;
Output:
From outer block: Invalid string length
EXCEPTION RAISED IN THE EXCEPTION
SECTION
Exceptions raised in the declarative secion
must be handled in the outer block.
Ex1:
DECLARE
e1 exception;
e2 exception;

BEGIN
raise e1;
EXCEPTION
when e1 then
dbms_output.put_line('e1 is
raised');
raise e2;
when e2 then
dbms_output.put_line('e2 is
raised');
END;
Output:
e1 is raised
DECLARE
*
ERROR at line 1:
defined exception
defined exception

Ex2:
DECLARE
e1 exception;
e2 exception;
BEGIN
BEGIN
raise e1;
EXCEPTION
when e1 then
dbms_output.put_line('e1
is raised');
raise e2;
when e2 then
dbms_output.put_line('e2
is raised');
END;
EXCEPTION
when e2 then
outer block: e2 is raised');
END;

Output:
e1 is raised
From outer block: e2 is raised
Ex3:
DECLARE
e exception;
BEGIN
raise e;
EXCEPTION
when e then
raised');
raise e;
END;
Output:
e is raised
DECLARE
*
ERROR at line 1:
defined exception

defined exception
RESTRICTIONS
You can not pass exception as an argument to a
subprogram.

DATABASE TRIGGERS
Triggers are similar to procedures or functions
in that they are named PL/SQL blocks with
declarative, executable, and exception handling
sections. A trigger is executed implicitly
whenever the triggering event happens. The
act of executing a trigger is known as firing the
trigger.
RESTRICTIONS ON TRIGGERES
1 Like packages, triggers must be stored as
stand-alone objects in the database and

cannot be local to a block or package.
1 A trigger does not accept arguments.
USE OF TRIGGERS
1 Maintaining complex integrity constraints
not possible through declarative
constraints enable at table creation.
1 Auditing information in a table by recording
the changes made and who made them.
1 Automatically signaling other programs
that action needs to take place when
changes are made to a table.
1 Perform validation on changes being made
to tables.
1 Automate maintenance of the database.
TYPES OF S
1 DML Triggers
1 Instead of Triggers
1 DDL Triggers
1 System Triggers

1 Suspend Triggers
CATEGORIES
Timing -- Before or After
Level -- Row or Statement
Row level trigger fires once for each row
affected by the triggering statement. Row level
trigger is identified by the FOR EACH ROW
clause.
Statement level trigger fires once either before
or after the statement.
DML TRIGGER SYNTAX
Create or replace trigger <trigger name>
{Before | after} {Insert or update or
delete} on <table name>
[For each row]
[When (…)]

[Declare]
-- Declaration
Begin
-- Trigger body
[Exception]
-- Exception section
End <trigger name>;
DML TRIGGERS
A DML trigger is fired on an INSERT, UPDATE,
or DELETES operation on a database table. It
can be fired either before or after the
statement executes, and can be fired once per
affected row, or once per statement.
The combination of these factors determines
the types of the triggers. These are a total of
12 possible types (3 statements * 2 timing * 2
levels).
STATEMENT LEVEL
Statement level trigger fires only once.

Ex:
SQL> create table statement level (count
varchar (50));
CREATE OR REPLACE TRIGGER
STATEMENT_LEVEL_TRIGGER
After update on student
BEGIN
Insert into statement level
values('Statement level fired');
END STATEMENT_LEVEL_TRIGGER;
Output:
SQL> update student set smarks=500;
3 rows updated.
SQL> select * from statement_level;
COUNT
----------------------------
Statement level fired

ROW LEVEL
Row level trigger fires once for each row
affected by the triggering statement.
Ex:
SQL> create table row_level(count
varchar(50));
ROW_LEVEL_TRIGGER
After update on student
BEGIN
Insert into row_level values ('Row level
fired');
END ROW_LEVEL_TRIGGER;
Output:
SQL> update student set smarks=500;

3 rows updated.
SQL> select * from statement_level;
COUNT
----------------------------
Row level fired
Row level fired
Row level fired
ORDER OF DML TRIGGER FIRING
1 Before statement level
1 Before row level
1 After row level
1 After statement level
Ex:
Suppose we have a follwing table.
NO NAME MARKS
----- ------- ----------

1 a 100
2 b 200
3 c 300
4 d 400
SQL> create table firing_order(order
varchar(50));
BEFORE_STATEMENT
before insert on student
BEGIN
insert into firing_order
values('Before Statement Level');
END BEFORE_STATEMENT;
BEFORE_ROW
before insert on student
for each row
BEGIN
insert into firing_order
values('Before Row Level');

END BEFORE_ROW;
AFTER_STATEMENT
after insert on student
BEGIN
insert into firing_order values('After
Statement Level');
END AFTER_STATEMENT;
AFTER_ROW
for each row
BEGIN
insert into firing_order values('After
Row Level');
END AFTER_ROW;
Output:
SQL> select * from firing_order;
no rows selected

values(5,'e',500);
1 row created.
SQL> select * from firing_order;
ORDER
----------------------------------------------
----
Before Statement Level
Before Row Level
After Row Level
After Statement Level
NO NAME MARKS
---- -------- ----------
1 a 100
2 b 200

3 c 300
4 d 400
5 e 500
CORRELATION IDENTIFIERS IN ROW-LEVEL
TRIGGERS
Inside the trigger, you can access the data in
the row that is currently being processed. This
is accomplished through two correlation
identifiers - :old and :new.
A correlation identifier is a special kind of
PL/SQL bind variable. The colon in front of each
indicates that they are bind variables, in the
sense of host variables used in embedded
PL/SQL, and indicates that they are not regular
PL/SQL variables. The PL/SQL compiler will
treat them as records of type
Triggering_table%ROWTYPE.
Although syntactically they are treated as
records, in reality they are not. :old and :new

are also known as pseudorecords, for this
reason.
TRIGGERING STATEMENT :OLD
:NEW
--------------------------------------
----------------------------
-----------------------------------------------
INSERT all fields are NULL.
values that will be inserted
When the statement is completed.
UPDATE original values for
new values that will be updated
the row before
the when the statement is completed.
update.
DELETE original values
before all fields are NULL.
the row is
deleted.
Ex:

SQL> create table marks(no number(2)
old_marks number(3),new_marks
number(3));
OLD_NEW
before insert or update or delete on
student
for each row
BEGIN
insert into marks
values(:old.no,:old.marks,:new.marks);
END OLD_NEW;
Output:
NO NAME MARKS
----- ------- ----------
1 a 100
2 b 200
3 c 300
4 d 400

5 e 500
SQL> select * from marks;
no rows selected
values(6,'f',600);
1 row created.
NO NAME MARKS
---- -------- ----------
1 a 100
2 b 200
3 c 300
4 d 400
5 e 500
6 f 600

NO OLD_MARKS NEW_MARKS
---- --------------- ---------------
600
SQL> update student set marks=555
where no=5;
1 row updated.
NO NAME MARKS
----- ------- ----------
1 a 100
2 b 200
3 c 300
4 d 400
5 e 555
6 f 600

------ ---------------- ---------------
600
5 500 555
1 row deleted.
NO NAME MARKS
---- -------- ----------
1 a 100
3 c 300
4 d 400
5 e 555
6 f 600
----- -------------- ----------------
600

5 500 555
2 200
REFERENCING CLAUSE
If desired, you can use the REFERENCING
clause to specify a different name for :old
ane :new. This clause is found after the
triggering event, before the WHEN clause.
Syntax:
REFERENCING [old as old_name] [new as
new_name]
Ex:
REFERENCE_TRIGGER
student
referencing old as old_student new
as new_student
for each row
BEGIN
insert into marks

values(:old_student.no,:old_student.m
arks,:new_student.marks);
END REFERENCE_TRIGGER;
WHEN CLAUSE
WHEN clause is valid for row-level triggers
only. If present, the trigger body will be
executed only for those rows that meet the
condition specified by the WHEN clause.
Syntax:
WHEN trigger_condition;
Where trigger_condition is a Boolean
expression. It will be evaluated for each row.
The :new and :old records can be referenced
inside trigger_condition as well, but like
REFERENCING, the colon is not used there. The
colon is only valid in the trigger body.
Ex:

WHEN_TRIGGER
student
referencing old as old_student new
as new_student
for each row
when (new_student.marks > 500)
BEGIN
insert into marks
values(:old_student.no,:old_student.m
arks,:new_student.marks);
END WHEN_TRIGGER;
TRIGGER PREDICATES
There are three Boolean functions that you can
use to determine what the operation is.
The predicates are
1 INSERTING
1 UPDATING
1 DELETING

Ex:
SQL> create table predicates(operation
varchar(20));
PREDICATE_TRIGGER
student
BEGIN
if inserting then
insert into predicates
values('Insert');
elsif updating then
values('Update');
elsif deleting then
values('Delete');
end if;
END PREDICATE_TRIGGER;

Output:
SQL> delete student where no=1;
1 row deleted.
SQL> select * from predicates;
MSG
---------------
Delete
values(7,'g',700);
1 row created.
MSG
---------------
Delete
Insert
SQL> update student set marks = 777

where no=7;
1 row updated.
MSG
---------------
Delete
Insert
Update
INSTEAD-OF TRIGGERS
Instead-of triggers fire instead of a DML
operation. Also, instead-of triggers can be
defined only on views. Instead-of triggers are
used in two cases:
1 To allow a view that would otherwise not
be modifiable to be modified.
1 To modify the columns of a nested table
column in a view.

Ex:
SQL> create view emp_dept as select
empno,ename,job,dname,loc,sal,e.deptno
from
emp e, dept d where e.deptno =
d.deptno;
INSTEAD_OF_TRIGGER
instead of insert on emp_dept
BEGIN
insert into dept1 values(50,'rd','bang');
insert into
emp1(empno,ename,job,sal,deptno)values(2
222,'saketh','doctor',8000,50);
END INSTEAD_OF_TRIGGER;
Output:
SQL> insert into emp_dept
values(2222,'saketh','doctor',8000,'rd','bang'
,50);
SQL> select * from emp_dept;

EMPNO ENAME JOB SAL
DNAME LOC DEPTNO
---------- ---------- ------------ -----------
------------- ------------- ----------
7369 SMITH CLERK 800
RESEARCH DALLAS 20
7499 ALLEN SALESMAN 1600
SALES CHICAGO 30
7521 WARD SALESMAN 1250
SALES CHICAGO 30
7566 JONES MANAGER 2975
RESEARCH DALLAS 20
7654 MARTIN SALESMAN 1250
SALES CHICAGO 30
7698 BLAKE MANAGER 2850
SALES CHICAGO 30
ACCOUNTING NEW YORK 10
7788 SCOTT ANALYST 3000
RESEARCH DALLAS 20
7839 KING PRESIDENT 5000

7844 TURNER SALESMAN 1500
SALES CHICAGO 30
7876 ADAMS CLERK 1100
RESEARCH DALLAS 20
7900 JAMES CLERK 950
SALES CHICAGO 30
7902 FORD ANALYST 3000
RESEARCH DALLAS 20
2222 saketh doctor 8000 rd
bang 50
DEPTNO DNAME LOC
---------- ---------------- -----------
20 RESEARCH DALLAS
30 SALES CHICAGO
50 rd bang

SQL> select * from emp;
EMPNO ENAME JOB MGR
---------- ---------- --------------- --------
-------------- --------- --------- ----------
7369 SMITH CLERK 7902
1 7-DEC-80 800 20
7499 ALLEN SALESMAN 7698
20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698
22-FEB-81 1250 500 30
7566 JONES MANAGER 7839
02-APR-81 2975 20
7654 MARTIN SALESMAN 7698
28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839
01-MAY-81 2850 30
09-JUN-81 2450 10

7788 SCOTT ANALYST 7566
19-APR-87 3000 20
7839 KING PRESIDENT
17-NOV-81 5000 10
7844 TURNER SALESMAN 7698
08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788
23-MAY-87 1100 20
7900 JAMES CLERK 7698
03-DEC-81 950 30
7902 FORD ANALYST 7566
03-DEC-81 3000 20
23-JAN-82 1300 10
2222 saketh doctor
8000 50
DDL TRIGGERS
Oracle allows you to define triggers that will
fire when Data Definition Language statements
are executed.

Syntax:
Create or replace trigger <trigger_name>
{Before | after} {DDL event} on
{database | schema}
[When (…)]
[Declare]
-- declaration
Begin
-- trigger body
[Exception]
End <trigger_name>;
Ex:
SQL> create table my_objects(obj_name
varchar(10),obj_type varchar(10),obj_owner
varchar(10),obj_time date);
CREATE_TRIGGER
after create on database

BEGIN
insert into my_objects
values(sys.dictionary_obj_name,sys.diction
ary_obj_type,
sys.dictio
nary_obj_owner, sysdate);
END CREATE_TRIGGER;
Output:
SQL> select * from my_objects;
no rows selected
SQL> create table stud1(no number(2));
OBJ_NAME OBJ_TYPE OBJ_OWNER
OBJ_TIME
------------- -------------- --------------
------------
STUD1 TABLE SYS 21-
JUL-07

SQL> create sequence ss;
SQL> create view stud_view as select * from
stud1;
OBJ_NAME OBJ_TYPE OBJ_OWNER
OBJ_TIME
-------------- ------------- ----------------
-------------
STUD1 TABLE SYS 21-
JUL-07
SS SEQUENCE SYS 21-
JUL-07
STUD_VIEW VIEW SYS 21-
JUL-07
WHEN CLAUSE
If WHEN present, the trigger body will be
executed only for those that meet the condition

specified by the WHEN clause.
Ex:
CREATE_TRIGGER
after create on database
when (sys.dictionary_obj_type =
‘TABLE’)
BEGIN
insert into my_objects
values(sys.dictionary_obj_name,sys.diction
ary_obj_type,
sys.dictio
nary_obj_owner, sysdate);
END CREATE_TRIGGER;
SYSTEM TRIGGERS
System triggers will fire whenever database-
wide event occurs. The following are the
database event triggers. To create system
trigger you need ADMINISTER DATABASE
TRIGGER privilege.

1 STARTUP
1 SHUTDOWN
1 LOGON
1 LOGOFF
1 SERVERERROR
Syntax:
{Before | after} {Database event} on
{database | schema}
[When (…)]
[Declare]
-- declaration section
Begin
-- trigger body
[Exception]
End <trigger_name>;
Ex:
SQL> create table user_logs(u_name

varchar(10),log_time timestamp);
AFTER_LOGON
after logon on database
BEGIN
insert into user_logs
values(user,current_timestamp);
END AFTER_LOGON;
Output:
SQL> select * from user_logs;
no rows selected
U_NAME LOG_TIME
----------
------------------------------------------------
SAKETH 22-JUL-07 12.07.13.140000 AM

SQL> conn system/oracle
U_NAME LOG_TIME
----------
------------------------------------------------
SAKETH 22-JUL-07 12.07.13.140000 AM
SYSTEM 22-JUL-07 12.07.34.218000 AM
SQL> conn scott/tiger
U_NAME LOG_TIME
----------
-----------------------------------------------
SAKETH 22-JUL-07 12.07.13.140000 AM
SYSTEM 22-JUL-07 12.07.34.218000 AM
SCOTT 22-JUL-07 12.08.43.093000 AM
SERVERERROR
The SERVERERROR event can be used to track

errors that occur in the database. The error
code is available inside the trigger through the
SERVER_ERROR attribute function.
Ex:
SQL> create table my_errors(error_msg
varchar(200));
SERVER_ERROR_TRIGGER
after servererror on database
BEGIN
insert into my_errors
values(dbms_utility.format_error_stack);
END SERVER_ERROR_TRIGGER;
Output:
SQL> create table ss (no));
create table ss (no))
*
ERROR at line 1:
ORA-00922: missing or invalid option

SQL> select * from my_errors;
ERROR_MSG
-----------------------------------------------------
--------
SQL> insert into student values(1,2,3);
insert into student values(1,2,3)
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> select * from my_errors;
ERROR_MSG
-----------------------------------------------------
--------
ORA-00942: table or view does not exist
SERVER_ERROR ATTRIBUTE FUNCTION
It takes a single number type of argument and

returns the error at the position on the error
stack indicated by the argument. The position 1
is the top of the stack.
Ex:
SERVER_ERROR_TRIGGER
after servererror on database
BEGIN
insert into my_errors
values(server_error(1));
END SERVER_ERROR_TRIGGER;
SUSPEND TRIGGERS
This will fire whenever a statement is
suspended. This might occur as the result of a
space issue such as exceeding an allocated
tablepace quota. This functionality can be used
to address the problem and allow the operatin
to continue.

Syntax:
after suspend on {database | schema}
[When (…)]
[Declare]
-- declaration section
Begin
-- trigger body
[Exception]
End <trigger_name>;
Ex:
SQL> create tablespace my_space datafile
'f:my_file.dbf' size 2m;
SQL> create table student(sno
number(2),sname varchar(10)) tablespace
my_space;
SUSPEND_TRIGGER

after suspend on database
BEGIN
dbms_output.put_line(‘ No room to
insert in your tablespace');
END SUSPEND_TRIGGER;
Output:
Insert more rows in student table then ,
you will get
No room to insert in your tablespace
AUTONOMOUS TRANSACTION
Prior to Oracle8i, there was no way in which
some SQL operations within a transaction could
be committed independent of the rest of the
operations. Oracle allows this, however,
through autonomous transactions. An
autonomous transaction is a transaction that is
started within the context of another
transaction, known as parent transaction, but
is independent of it. The autonomous

transaction can be committed or rolled back
regardless ot the state of the parent
transaction.
Ex:
AUTONOMOUS_TRANSACTION_TRIGGER
DECLARE
pragma autonomous_transaction;
BEGIN
update student set marks = 555;
commit;
END
AUTONOMOUS_TRANSACTION_TRIGGER;
Output:
NO NA MARKS
----- ----- -- ----------
1 a 111

2 b 222
3 c 300
SQL> insert into student values(4,'d',444);
NO NA MARKS
---- ------ -- ----------
1 a 555
2 b 555
3 c 555
4 d 444
RESTRICTIONS ON AUTONOMOUS
TRANSACTION
1 If an autonomous transaction attempts to
access a resource held by the main
transaction, a deadlock can occur in you
program.
1 You cannot mark all programs in a package
as autonomous with a single PRAGMA

declaration. You must indicate autonomous
transactions explicity in each program.
1 To exit without errors from an autonomous
transaction program that has executed at
least one INSERT or UPDATE or DELETE,
you must perform an explicit commit or
rollback.
1 The COMMIT and ROLLBACK statements
end the active autonomous transaction, but
they do not force the termination of the
autonomous routine. You can have multiple
COMMIT and/or ROLLBACK statements
inside your autonomous block.
1 You can not rollback to a savepoint set in
the main transaction.
1 The TRANSACTIONS parameter in the
oracle initialization file specifies the
maximum number of transactions allowed
concurrently in a session. The default value
is 75 for this, but you can increase the
limit.

MUTATING TABLES
There are restrictions on the tables and
columns that a trigger body may access. In
order to define these restrictions, it is
necessary to understand mutating and
constraining tables.
A mutating table is table that is currentlty
being modified by a DML statement and the
trigger event also DML statement. A mutating
table error occurs when a row-level trigger
tries to examine or change a table that is
already undergoing change.
A constraining table is a table that might need
to be read from for a referential integrity
constraint.
Ex:
MUTATING_TRIGGER
before delete on student

for each row
DECLARE
ct number;
BEGIN
select count(*) into ct from student
where no = :old.no;
END MUTATING_TRIGGER;
Output:
delete student where no = 1
*
ERROR at line 1:
ORA-04091: table SCOTT.STUDENT is
mutating, trigger/function may not see it
ORA-06512: at "SCOTT.T", line 4
ORA-04088: error during execution of
trigger 'SCOTT.T'
HOW TO AVOID MUTATING TABLE ERROR ?
1 By using autonomous transaction

1 By using statement level trigger

Best sql plsql material

Recommended

More Related Content

What's hot (20)

Viewers also liked (6)

Similar to Best sql plsql material (20)

Recently uploaded (20)

Best sql plsql material