ORACLE, SQL, PL/SQL Made very very Easy Happy Learning....

ORACLE
Hi all,
This is Oracle , SQL, PL-SQL Document which is made easy for
the beginners and as well as Intermediates.
Happy Learning….
Topics Covered:
 INTRODUCTION
 CONDITIONAL SELECTIONS AND OPERATORS
 MULTIBLE INSERTS
 FUNCTIONS
 CONSTRAINTS
 CASE AND DEFAULT
 ABSTRACT DATA TYPES
 OBJECT VIEWS AND METHODS
 VARRAYS AND NESTED TABLES
 FLASHBACK QUERY
 EXTERNAL TABLES
 REF DEREF VALUE
 OBJECT VIEWS WITH REFERENCES
 PARTITIONS
 ROLLUP GROUPING CUBE
 SET OPERATORS
 VIEWS
 SYNONYM AND SEQUENCE
 JOINS
 SUBQUERIES AND EXISTS
 WALKUP TREES AND INLINE VIEW
 LOCKS
 INDEXES
 SET COMMANDS
 SPECIAL FILES
 IMP QUERIES
 SQL
 PL-SQL
 ERROR HANDLING
 DATABASE TRIGGERS & etc……..

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INTRODUCTION
SQL is divided into the following
 Data Definition Language (DDL)
 Data Manipulation Language (DML)
 Data Retrieval Language (DRL)
 Transaction Control Language (TCL)
 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.
 By value method
 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);

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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’);
SQL> insert into student (no, name) values (4, ’Madhu’);

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d) INSERTING DATA INTO SPECIFIED COLUMNS USING ADDRESS METHOD
Syntax:
insert into <table_name)(col1, col2, col3 … coln) 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 (no, name) values (&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

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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

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CONDITIONAL SELECTIONS AND OPERATORS
We have two clauses used in this
 Where
 Order by
USING WHERE
Syntax:
select * from <table_name> where <condition>;
the following are the different types of operators used in where clause.
 Arithmetic operators
 Comparison operators
 Logical operators
 Arithmetic operators -- highest precedence
+, -, *, /
 Comparison operators
 =, !=, >, <, >=, <=, <>
 between, not between
 in, not in
 null, not null
 like
 Logical operators
 And
 Or -- lowest precedence
 not
a) USING =, >, <, >=, <=, !=, <>
Ex:
SQL> select * from student where no = 2;
NO NAME MARKS
--- ------- ---------
2 Saketh 200

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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

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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

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2 Naren 400
c) USING OR
This will gives the output when either of the conditions become true.
Syntax:
select * from <table_name> where <condition1> and <condition2> or ..
<conditionn>;
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, upperbound.
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

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e) USING NOT BETWEEN
This will gives the output based on the column which values are not in its lower bound,
upperbound.
Syntax:
select * from <table_name> where <col> not between <lower bound> and <upper
bound>;
Ex:
SQL> select * from student where marks not between 200 and 400;
NO NAME MARKS
--- ------- ---------
1 Sudha 100
f) USING IN
This will gives the output based on the column and its list of values specified.
Syntax:
select * from <table_name> where <col> 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.

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Syntax:
select * from <table_name> where <col> 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:
select * from <table_name> where <col> is null;
Ex:
SQL> select * from student where marks 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:
select * from <table_name> where <col> is not null;

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Ex:
SQL> select * from student where marks 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:
select * from <table_name> where <col> 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’.
SQL> select * from student where name like 'S%';
NO NAME MARKS
--- ------- ---------
1 Sudha 100
2 Saketh 200
iii) This will give the rows whose name ends with ‘h’.
SQL> select * from student where name like '%h';

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NO NAME MARKS
--- ------- ---------
2 Saketh 200
3 Ramesh
iV) This will give the rows whose name’s second letter start with ‘a’.
SQL> select * from student where 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’.
SQL> select * from student where 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.
SQL> select * from student where 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.

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SQL> select * from student where name like '%e__%';
NO NAME MARKS
--- ------- ---------
2 Saketh 200
3 Ramesh
Viii) This will give the rows whose name cotains 2 a’s.
SQL> select * from student where 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 200
2 Naren 400
3 Ramesh
4 Madhu

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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 will update entire table.
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.

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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);

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* 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

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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.
 Implicit
 Explicit
a) IMPLICIT
This will be issued by oracle internally in two situations.
 When any DDL operation is performed.
 When you are exiting from SQL * PLUS.
b) EXPLICIT
This will be issued by the user.

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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.
 Upto previous commit
 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

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--- ------- ----------
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

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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.

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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;

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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);

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MULTIBLE 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’)
Into student(name,marks) values(’e’,400)
d) MULTI INSERT WITH DUPLICATE ROWS
SQL> insert all

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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

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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

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** You can use multi tables with specified fields, with duplicate rows, with conditions,
with
first and else clauses.

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FUNCTIONS
Functions can be categorized as follows.
 Single row functions
 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.
 Numeric functions
 String functions
 Date functions
 Miscellaneous functions
 Conversion functions
NUMERIC FUNCTIONS
 Abs
 Sign
 Sqrt
 Mod
 Nvl
 Power
 Exp
 Ln
 Log
 Ceil
 Floor
 Round
 Trunk
 Bitand
 Greatest
 Least
 Coalesce
a) ABS

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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

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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;

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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

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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

ORACLE
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)

ORACLE
--------------------- ------------------------ ----------------------- ----------------------
-
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)
----------------------- -------------- -------------- ---------------- ----------------

ORACLE
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;

ORACLE
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

ORACLE
 If all the values are zeros then it will display zero.
 If all the parameters are nulls then it will display nothing.
 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
 If all the values are zeros then it will display zero.
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
 Initcap
 Upper
 Lower
 Length

ORACLE
 Rpad
 Lpad
 Ltrim
 Rtrim
 Trim
 Translate
 Replace
 Soundex
 Concat ( ‘ || ‘ Concatenation operator)
 Ascii
 Chr
 Substr
 Instr
 Decode
 Greatest
 Least
 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;

ORACLE
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:

ORACLE
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

ORACLE
---------- ----------
computer computer
-- If you haven’t specify any unwanted characters it will display entire string.
h) RTRIM
This will trim off unwanted characters from 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
This will trim off unwanted characters from 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

ORACLE
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

ORACLE
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

ORACLE
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
 If no_of_chars parameter is negative then it will display nothing.

ORACLE
 If both parameters except string are null or zeros then it will display nothing.
 If no_of_chars parameter is greater than the length of the string then it ignores
and calculates based on the orginal string length.
 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
 If you are not specifying start_chr_count and occurrence then it will start search
from
the beginning and finds first occurrence only.
 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

ORACLE
----- ---------
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
 If the number of parameters are odd and different then decode will display
nothing.
 If the number of parameters are even and different then decode will display last
value.
 If all the parameters are null then decode will display nothing.
 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

ORACLE
------- -------
c srinu
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
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
 Sysdate
 Current_date

ORACLE
 Current_timestamp
 Systimestamp
 Localtimestamp
 Dbtimezone
 Sessiontimezone
 To_char
 To_date
 Add_months
 Months_between
 Next_day
 Last_day
 Extract
 Greatest
 Least
 Round
 Trunc
 New_time
 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.

ORACLE
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
---------------------------------------------------------------------------

ORACLE
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

ORACLE
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
----------------------------------------------------

ORACLE
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 date format.

ORACLE
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
 If no_of_months is zero then it will display the same date.
 If no_of_months is null then it will display nothing.
k) MONTHS_BETWEEN
This will give difference of months between two dates.

ORACLE
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)

ORACLE
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

ORACLE
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.

ORACLE
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.
 If the second parameter was null then it returns nothing.
 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.
 If the you are not specifying the second 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

ORACLE
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))
 If the second parameter was year then it always returns the first day of the current
year.
 If the second parameter was month then it always returns the first day of the current
month.
 If the second parameter was day then it always returns the previous sunday.
 If the second parameter was null then it returns nothing.
 If the you are not specifying the second 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

ORACLE
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:

ORACLE
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
 Uid
 User
 Vsize
 Rank
 Dense_rank
a) UID
This will returns the integer value corresponding to the user currently logged in.

ORACLE
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
---------- ----------

ORACLE
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(ORDERBYSALDESC)
---------------------------------------------------------
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(ORDERBYSALDESC)
-----------------------------------------------------------------
3
CONVERSION FUNCTIONS
 Bin_to_num
 Chartorowid
 Rowidtochar
 To_number
 To_char

ORACLE
 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
 If all the bits are zero then it produces zero.
 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

ORACLE
 Sum
 Avg
 Max
 Min
 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 the specified column.
Syntax: max (column)

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

ORACLE
CONSTRAINTS
Constraints are categorized as follows.
Domain integrity constraints
 Not null
 Check
Entity integrity constraints
 Unique
 Primary key
Referential integrity constraints
 Foreign key
Constraints are always attached to a column not a table.
We can add constraints in three ways.
 Column level -- along with the column definition
 Table level -- after the table definition
 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));
SQL> create table student(no number(2) constraint nn not null, name varchar(10), marks
number(3));
CHECK

ORACLE
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));
SQL> create table student(no number(2) , name varchar(10), marks number(3) constraint
ch
check(marks > 300));
TABLE LEVEL
SQL> create table student(no number(2) , name varchar(10), marks number(3), check
(marks > 300));
SQL> create table student(no number(2) , 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.
Ex:
COLUMN LEVEL
SQL> create table student(no number(2) unique, name varchar(10), marks number(3));
SQL> create table student(no number(2) constraint un unique, name varchar(10), marks
number(3));
TABLE LEVEL

ORACLE
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
This is used to avoid duplicates and nulls. This will work as combination of unique and not
null.
Primary key always attached to the parent table.
Ex:
COLUMN LEVEL
SQL> create table student(no number(2) primary key, name varchar(10), marks
number(3));
SQL> create table student(no number(2) 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

ORACLE
This is used to reference the parent table primary key column which allows duplicates.
Foreign key always attached to the child table.
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

ORACLE
SQL> alter table emp add foreign key(deptno) references dept(deptno) on delete cascade;
SQL> alter table emp add constraint fk 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);
SQL> alter table student add constraint un 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)
SQL> create table emp(empno number(2), ename varchar(10), deptno number(2), dname

ORACLE
varchar(10), primary key(empno), foreign key(deptno,dname) references
dept(deptno,dname));
SQL> create table emp(empno number(2), ename varchar(10), deptno number(2), dname
varchar(10), constraint pk primary key(empno), constraint fk foreign
key(deptno,dname) references dept(deptno,dname));
FOREIGN KEY (ALTER LEVEL)
SQL> alter table emp add foreign key(deptno,dname) references dept(deptno,dname);
SQL> alter table emp add constraint fk foreign key(deptno,dname) references
dept(deptno,dname);
DEFERRABLE CONSTRAINTS
Each constraint has two additional attributes to support deferred checking of constraints.
 Deferred initially immediate
 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), name varchar(10), marks number(3), constraint
un unique(no) deferred initially immediate);
SQL> create table student(no number(2), name varchar(10), marks number(3), constraint
un unique(no) deferred initially deferred);
SQL> alter table student add constraint un 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

ORACLE
Possible operations with constraints as follows.
 Enable
 Disable
 Enforce
 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.

ORACLE
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

ORACLE
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:
SQL> create table student(no number(2) 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.

ORACLE
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'));
SQL> insert into student values(2,'b',addr(222,'bang'));
SQL> insert into student 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

ORACLE
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;
---- ------- ----------------- ----------------
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;
---- ------- ----------------- ----------------
2 b 222 bang
3 c 333 bombay
DROPPING ADT
SQL> drop type addr;

ORACLE
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> create table student(no number(2),name varchar(10),hno number(3),city
varchar(10));
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,fnps));/
2) Defining type body

ORACLE
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
SQL> Create table student(no number(2),info stud);
4) Insert some data into student table
SQL> Insert into student 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.

ORACLE
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 number(3),city varchar(10));/
SQL> Create type va as varray(5) of addr;/
2) Using varray in table
SQL> Create table student(no number(2),name varchar(10),address va);
3) Inserting values into varray table
SQL> Insert into student values(1,’sudha’,va(addr(111,’hyd’)));
SQL> Insert into student values(2,’jagan’,va(addr(111,’hyd’),addr(222,’bang’)));
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:

ORACLE
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 number(3),city varchar(10));/
SQL> Create type nt as table of addr;/
2) Using nested table in table
SQL> Create table student(no 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
 ALL_COLL_TYPES
 ALL_TYPES
 DBA_COLL_TYPES
 DBA_TYPES
 USER_COLL_TYPES
 USER_TYPES

ORACLE
FLASHBACK QUERY
Used to retrieve the data which has been already committed with out going for recovery.
Flashbacks are of two types
 Time base flashback
 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_number(:s)
SQL> Exec dbms_flashback.disable

ORACLE
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),

ORACLE
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
a) Indexing not possible
b) 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
b) You can join external tables to each other or to standard tables
REF DEREF VALUE
REF
 The ref function allows referencing of existing row objects.
 Each of the row objects has an object id value assigned to it.
 The object id assigned can be seen by using ref function.
DEREF
 The deref function performs opposite action.
 It takes a reference value of object id and returns the value of the row objects.
VALUE
 Even though the primary table is object table, still it displays the rows in general
format.
 To display the entire structure of the object, this will be used.

ORACLE
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
SQL> Create table orders (order_no 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));
SQL> insert into orders values(12,(select ref(v) from vendors v where vendor_code =
2));
SQL> insert into orders values(13,(select ref(v1) from vendors1 v1 where vendor_code
=
1));
SQL> insert into orders values(14,(select 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

ORACLE
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 wih the type.
REF CONSTRAINTS
Ref can also acts as constraint.
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.
The vendor_info column in the following syntaxes will store object ids of vendors only.
SQL> Create table orders (order_no number(2), vendor_info ref vendor_adt scope is
vendors);
Or
SQL> Create table orders (order_no 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 constrains.
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));

ORACLE
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
 Range partitions
 List partitions
 Hash partitions
 Sub partitions

ORACLE
ADVANTAGES
 Reducing downtime for scheduled maintenance, which allows maintenance operations
to be carried out on selected partitions while other partitions are available to users.
 Reducing downtime due to data failure, failure of a particular partition will no way
affect other partitions.
 Partition independence allows for concurrent use of the various partitions for various
purposes.
ADVANTAGES OF PARTITIONS BY STORING THEM IN DIFFERENT TABLESPACES
 Reduces the possibility of data corruption in multiple partitions.
 Back up and recovery of each partition can be done independently.
DISADVANTAGES
 Partitioned tables cannot contain any columns with long or long raw datatypes, LOB
types or object types.
RANGE PARTITIONS
a) Creating range partitioned table
SQL> Create table student(no 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;

ORACLE
SQL> Select *from student partition(p1);
d) Possible operations with range partitions
 Add
 Drop
 Truncate
 Rename
 Split
 Move
 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
SQL> Create table student(no number(2),name varchar(2)) partition by 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
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

ORACLE
d) Possible operations with list partitions
 Add
 Drop
 Truncate
 Rename
 Move
 Exchange
SQL> Alter table student add partition p5 values(21,22,23,24,25);
i) Exchanging a partition
SQL> Alter table student exchange 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
SQL> Create table student(no number(2),name varchar(2)) partition by 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’);

ORACLE
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
 Add
 Truncate
 Rename
 Move
 Exchange
SQL> Alter table student add partition p6 ;
f) Renaming a partition
g) Truncate a partition
h) Exchanging a partition
SQL> Alter table student exchange 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
SQL> Create table student(no 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

ORACLE
SYS_SUBP6
** if you are using maxvalue for the last partition, you can not add a partition.
b) Inserting records into subpartitioned table
c) Retrieving records from subpartitioned table
SQL> Select *from student subpartition(sys_subp1);
d) Possible operations with subpartitions
 Add
 Drop
 Truncate
 Rename
 Split
SQL> Alter table student add partition p3 values less than(30);
i) Splitting a partition
SQL> Alter table student split partition p3 at(15) into (partition p31,partition p32);
DATA MODEL
 ALL_IND_PARTITIONS
 ALL_IND_SUBPARTITIONS
 ALL_TAB_PARTITIONS
 ALL_TAB_SUBPARTITIONS
 DBA_IND_PARTITIONS
 DBA_IND_SUBPARTITIONS
 DBA_TAB_PARTITIONS
 DBA_TAB_SUBPARTITIONS
 USER_IND_PARTITIONS
 USER_IND_SUBPARTITIONS

ORACLE
 USER_TAB_PARTITIONS
 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

ORACLE
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
 Group the rows together based on group by clause.
 Calculate the group functions for each group.
 Choose and eliminate the groups based on the having clause.
 Order the groups based on the specified column.

ORACLE
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
fot 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);

ORACLE
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

ORACLE
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
 Union
 Union all
 Intersect
 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

ORACLE
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;
VIEWS
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
 Simple view
 Complex view
Simple view can be created from one table where as complex view can be created from
multiple tables.
WHY VIEWS?
 Provides additional level of security by restricting access to a predetermined set of
rows and/or columns of a table.
 Hide the data complexity.
 Simplify commands for the user.
VIEWS WITHOUT DML
 Read only view
 View with group by
 View with aggregate functions

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

ORACLE
- Insert possible with marks value as 500
- Update possible excluding marks column
- Delete possible
DROPPING VIEWS
SQL> drop view dept_v;
SYNONYM AND SEQUENCE
SYNONYM
A synonym is a database object, which is used as an alias for a table, view or sequence.
TYPES
 Private
 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
 Hide the name and owner of the object.
 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.

ORACLE
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> create sequence s increment by 10 start with 100 minvalue 5 maxvalue 200 cycle
cache 20;
USING SEQUENCE
SQL> create table student(no number(2),name varchar(10));
SQL> insert into student values(s.nextval, ‘saketh’);
 Initially currval is not defined and nextval is starting value.
 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.
 Set or eliminate minvalue or maxvalue.
 Change the increment value.
 Change the number of cached sequence numbers.
Ex:
SQL> alter sequence s minvalue 5;
SQL> alter sequence s increment by 2;

ORACLE
SQL> alter sequence s cache 10;
DROPPING SEQUENCE
SQL> drop sequence s;
JOINS
The purpose of a join is to combine the data across tables.
A join is actually performed by the where clause which combines the specified rows of
tables.
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
Equi join
Non-equi join
Self join
Natural join
Cross join
Outer join
 Left outer
 Right outer
 Full outer
Inner join
Using clause
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;

ORACLE
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);
---------- ---------- ---------- ---------- ----------
ON CLAUSE
SQL> select empno,ename,job,dname,loc from emp e join dept d on(e.deptno=d.deptno);
---------- ---------- ---------- ---------- ----------

ORACLE
NON-EQUI JOIN
A join which contains an operator other than ‘=’ in the joins condition.
Ex:
SQL> select empno,ename,job,dname,loc from emp e,dept d where e.deptno > d.deptno;
---------- ---------- ---------- ---------- ----------
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:
SQL> select empno,ename,job,dname,loc from emp natural join dept;

ORACLE
---------- ---------- ---------- ---------- ----------
CROSS JOIN
This will gives the cross product.
Ex:
SQL> select empno,ename,job,dname,loc from emp cross join dept;
---------- ---------- ---------- ---------- ----------
222 sudha clerk mkt hyd
444 madhu engineer mkt hyd
111 saketh analyst 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:

ORACLE
SQL> select empno,ename,job,dname,loc from emp e left outer join dept d
on(e.deptno=d.deptno);
Or
SQL> select empno,ename,job,dname,loc from emp e,dept d where
e.deptno=d.deptno(+);
---------- ---------- ---------- ---------- ----------
444 madhu engineer
RIGHT OUTER JOIN
This will display the all matching records and the records which are in right hand side table
those that are not in left hand side table.
Ex:
SQL> select empno,ename,job,dname,loc from emp e right outer join dept d
Or
SQL> select empno,ename,job,dname,loc from emp e,dept d where e.deptno(+) =
d.deptno;
---------- ---------- ---------- ---------- ----------
hr bombay
FULL OUTER JOIN
This will display the all matching records and the non-matching records from both tables.
Ex:
SQL> select empno,ename,job,dname,loc from emp e full outer join dept d

ORACLE
---------- ---------- ---------- ---------- ----------
444 madhu engineer
hr bombay
INNER JOIN
This will display all the records that have matched.
Ex:
SQL> select empno,ename,job,dname,loc from emp inner join dept using(deptno);
---------- ---------- ---------- ---------- ----------
SUBQUERIES AND EXISTS
SUBQUERIES
Nesting of queries, one within the other is termed as a subquery.
A statement containing a subquery is called a parent query.
Subqueries are used to retrieve data from tables that depend on the values in the table
itself.
TYPES
 Single row subqueries
 Multi row subqueries
 Multiple subqueries
 Correlated subqueries

ORACLE
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);
---------- ---------- --------- ---------- ----------- -------- ---------- ----------
7566 JONES MANAGER 7839 02-APR-81 2975 20
7902 FORD ANALYST 7566 03-DEC-81 3000 20
SQL> select * from emp where sal > all (select sal from emp where sal between 2500 and
4000);
---------- ---------- --------- ---------- ------------- ------ ---------- ----------

ORACLE
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));
---------- ---------- --------- ---------- ------------ ------- ---------- ----------
7902 FORD ANALYST 7566 03-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

ORACLE
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;

ORACLE
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

ORACLE
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

ORACLE
LOCKS
Locks are the mechanisms used to prevent destructive interaction between users accessing
same resource simultaneously. Locks provides high degree of data concurrency.
TYPES
 Row level locks
 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.
 Share lock
 Share update lock
 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

ORACLE
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 tow 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.

ORACLE
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
 Unique index
 Non-unique index
 Btree index
 Bitmap index
 Composite index
 Reverse key index
 Function-based index
 Descending index
 Domain index
 Object index
 Cluster index
 Text index
 Index organized table
 Partition index
 Local index
 Local prefixed
 Local non-prefixed
 Global index
 Global prefixed
 Global non-prefixed
UNIQUE INDEX

ORACLE
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:
SQL> create index stud_ind on student(sno);
BITMAP INDEX
This can be used for low cardinality columns: that is columns in which the number of distinct
values is snall when compared to the number of the rows in the table.
Ex:
SQL> create bitmap index stud_ind on student(sex);

ORACLE
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:
SQL> create index stud_ind on student(upper(sname));
DESCENDING INDEX

ORACLE
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 collection 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.
 CONTEXT
 CTXCAT
 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.

ORACLE
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;
SQL> create index book_index on books(info) 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;

ORACLE
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.
SQL> select * from books where contains(info, ‘property AND harvests’) > 0;
SQL> select * from books where catsearch(info, ‘property AND harvests’, null) > 0;
Instead of using AND you could hae 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
SQL> select * from books where contains(info, ‘property & harvests’) > 0;
SQL> select * from books where catsearch(info, ‘property harvests’, null) > 0;
The following queries will search for more than two words.
SQL> select * from books where contains(info, ‘property AND harvests AND workers’) > 0;
SQL> select * from books where catsearch(info, ‘property harvests workers’, null) > 0;
The following queries will search for either of the two words.
SQL> select * from books where contains(info, ‘property OR harvests’) > 0;
Instead of OR you can use a vertical line (|).
SQL> select * from books where contains(info, ‘property | harvests’) > 0;
SQL> select * from books where 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.
SQL> select * from books where contains(info, ‘property ACCUM harvests’) > 0;
SQL> select * from books where catsearch(info, ‘property ACCUM harvests’, null) > 0;

ORACLE
Instead of OR you can use a comma(,).
SQL> select * from books where contains(info, ‘property , harvests’) > 0;
SQL> select * from books where 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.
SQL> select * from books where contains(info, ‘property MINUS harvests’) > 0;
SQL> select * from books where catsearch(info, ‘property NOT harvests’, null) > 0;
Instead of MINUS you can use – and instead of NOT you can use ~.
SQL> select * from books where contains(info, ‘property - harvests’) > 0;
SQL> select * from books where 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.
SQL> select * from books where contains(info, ‘transactions {and} finances’) > 0;
SQL> select * from books where 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.
SQL> select * from books where contains(info, ‘{transactions and finances}’) > 0;
SQL> select * from books where 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.
SQL> select * from books where contains(info, ‘workers NEAR harvests’) > 0;
Instead of NEAR you can use ;.

ORACLE
SQL> select * from books where contains(info, ‘workers ; harvests’) > 0;
In CONTEXT index queries, you can specify the maximum number of words between the
search terms.
SQL> select * from books where contains(info, ‘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
SQL> select * from books where contains(info, ‘worker%’) > 0;
SQL> select * from books where contains(info, ‘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
SQL> select * from books where contains(info, ‘$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’.
SQL> select * from books where contains(info, ‘hardest’) > 0;

ORACLE
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.
SQL> select * from books where contains(info, ‘?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(!).
SQL> select * from books where contains(info, ‘!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_set’);

ORACLE
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.
SQL> create index book_index on books(info) 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
 Local keyword tells oracle to create a separte index for each partition.
 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.
 Local prefixed indexes can be unique or non unique.
 Local indexes may be easier to manage than global indexes.
Ex:
SQL> create index stud_index on student(sno) local;

ORACLE
GLOBAL INDEXES
 A global index may contain values from multiple partitions.
 An index is global prefixed if it is partitioned on the left prefix of the index columns.
 The global clause allows you to create a non-partitioned index.
 Global indexes may perform uniqueness checks faster than local (partitioned)
indexes.
 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
 Index partitions cannot be dropped manually.
 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.

ORACLE
Syntax:
alter index index_name nomonitoring usage;
DATA MODEL
 ALL_INDEXES
 DBA_INDEXES
 USER_INDEXES
 ALL_IND-COLUMNS
 DBA-IND_COLUMNS
 USER_IND_COLUMNS
 ALL_PART_INDEXES
 DBA_PART_INDEXES
 USER_PART_INDEXES
 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]

ORACLE
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
-----------------------
---------- ---------- --------- ------- -------------- -------- ---------- ----------
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7839 KING PRESIDENT 17-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

ORACLE
7902 FORD ANALYST 7566 03-DEC-81 3000
7788 SCOTT ANALYST 7566 19-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

ORACLE
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

ORACLE
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
--------- -------------- ----------

ORACLE
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

ORACLE
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

ORACLE
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

ORACLE
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:

ORACLE
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

ORACLE
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

ORACLE
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.

ORACLE
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.

ORACLE
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

ORACLE
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

ORACLE
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

ORACLE
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

ORACLE
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:

ORACLE
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:

ORACLE
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

ORACLE
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.

ORACLE
IMP 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,deptno);
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);

ORACLE
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);

ORACLE
INTRODUCTION
CHARACTERSTICS
 Highly structured, readable and accessible language.
 Standard and Protable language.
 Embedded language.
 Improved execution authority.
10g FEATURES
 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;
 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.

ORACLE
SQL> alter session set plsql_warnings = ‘enable:all’;
The above can be achieved using the built-in package DBMS_WARNING.
 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.
 Support for non-sequential collections in FORALL.
 Improved datatype support.
 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_BACKTRACE function to obtain that stack
and manipulate it programmatically within your program.
 Set operators for nested tables.
 Support for regular expressions.
Oracle database 10g supports the use of regular expressions inside PL/SQL code via
four new built-in functions.
 REGEXP_LIKE
 REGEXP_INSTR
 REGEXP_SUBSTR
 REGEXP_REPLACE
 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.

ORACLE
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
 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
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 exceptiona sections are optional.
BLOCK TYPES
 Anonymous blocks
 Named blocks
 Labeled blocks
 Subprograms
 Triggers
ANONYMOUS BLOCKS
Anonymous blocks implies basic block structure.
Ex:
BEGIN
Dbms_output.put_line(‘My first program’):
END;
LABELED BLOCKS

ORACLE
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

ORACLE
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.
 Single line comments
 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;

ORACLE
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 achoring.
 Scalar anchoring
 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;

ORACLE
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
 Synchronization with database columns.
 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.
 Constrained
 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;

ORACLE
DATATYPE CONVERSIONS
PL/SQL can handle conversions between different families among the datatypes.
Conversion can be done in two ways.
 Explicit conversion
 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
 Characters and numbers
 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.

ORACLE
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

ORACLE
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.
 If-then-else
 Case
 Case with no else
 Labeled case
 Searched case
 Simple loop
 While loop
 For loop
 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

ORACLE
dbms_output.put_line('Location is DALLAS');
elsif dno = 30 then
dbms_output.put_line('Location is CHICAGO');
else
dbms_output.put_line('Location is BOSTON');
end if;
END;
Output:
Location is NEW YORK
CASE
Syntax:
Case test-variable
When value1 then sequence of statements;
……
When valuen then sequence of statements;
Else sequence of statements;
End case;
Ex:
DECLARE
dno number(2);
BEGIN
case dno
when 10 then
when 20 then
when 30 then
else
end case;
END;

ORACLE
Output:
CASE WITHOUT ELSE
Syntax:
Case test-variable
……
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:

ORACLE
<<label>>
Case test-variable
……
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;

ORACLE
Ex:
DECLARE
dno number(2);
BEGIN
case dno
when dno = 10 then
when dno = 20 then
when dno = 30 then
when dno = 40 then
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);

ORACLE
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
i := i + 1;
end loop;
END;
Output:
i = 1
i = 2
i = 3
i = 4
i = 5
FOR LOOP
Syntax:

ORACLE
For <loop_counter_variable> in low_bound..high_bound loop
End loop;
Ex1:
BEGIN
For i in 1..5 loop
end loop;
END;
Output:
i = 1
i = 2
i = 3
i = 4
i = 5
Ex2:
BEGIN
For i in reverse 1..5 loop
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.

ORACLE
 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.
 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.
 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
if i = 4 then
goto exit_loop;
end if;
end loop;
<<exit_loop>>
Null;
END;
Output:

ORACLE
i = 1
i = 2
i = 3
i = 4
RESTRICTIONS ON GOTO
 It is illegal to branch into an inner block, loop.
 At least one executable statement must follow.
 It is illegal to branch into an if statement.
 It is illegal to branch from one if statement to another if statement.
 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:
 AUTONOMOUS_TRANSACTION
 EXCEPTION_INIT
 RESTRICT_REFERENCES
 SERIALLY_REUSABLE

ORACLE
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.

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

ORACLE
procedure p(a in number, b in number default 6, c in number) – invalild
procedure p(a in number default 5, b in number default 6, c in number) – invalild
procedure p(a in number default 5, b in number, c in number) – invalild
NOTATIONS
Notations are of two types.
 Positional notation
 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
 Parametes which are in calling subprogram are actual parameters.
 Parametes which are in called subprogram are formal parameters.
 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 number)
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');

ORACLE
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);
dbms_output.put_line('After completion of call');
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;
dbms_output.put_line('After assignment');
dbms_output.put_line('a = ' || a || ' b = ' || b || ' c = ' || c);
return (a*b*c);
END FUN;
DECLARE

ORACLE
v1 number := 1;
v2 number := 2;
v3 number := 3;
v number;
BEGIN
dbms_output.put_line('Before call');
v := fun(v1,v2,v3);
dbms_output.put_line('After call completed');
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
 By declaring with specified size in actual parameters.
 By declaring formal parameters with %type specifier.
USING NOCOPY
 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.
 The copying from formal to actual can be restricted by issuing nocopy qualifier.
 To pass the out and in out parameters by reference use nocopy qualifier.

ORACLE
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];
 The parantheses are always required, even if the subprogram takes no arguments.
 We can not use call with out and in out parameters.
 Call is a SQL statement, it is not valid inside a PL/SQL block;
 The INTO clause is used for the output variables of functions only.
 We can not use ‘exec’ with out or in out parameters.
 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:

ORACLE
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
 In parameters by default call by reference where as out and in out call by value.
 When parameter passed by reference, a pointer to the actual parameter is passed to
the
corresponding formal parameter.
 When parameter passed by value it copies the value of the actual parameter to the
formal parameter.
 Call by reference is faster than the call by value because it avoids the copying.
SUBPROGRAMS OVERLOADING
 Possible with different number of parameters.
 Possible with different types of data.
 Possible with same type with objects.
 Can not be possible with different types of modes.
 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);

ORACLE
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
 Supporting many data combinations
 Fitting the program to the user.
RESTRICTIONS ON OVERLOADING
 Overloaded programs with parameter lists that differ only by name must be called
using named notation.
 The parameter list of overloaded programs must differ by more than parameter mode.
 All of the overloaded programs must be defined within the same PL/SQL scope or
block.
 Overloaded functions must differ by more than their return type.

ORACLE
IMPORTANT POINTS ABOUT SUBPROGRAMS
 When a stored subprogram is created, it is stored in the data dictionary.
 The subprogram is stored in compile form which is known as p-code in addition to the
source text.
 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.
 When the subprogram is called, the p-code is read from the disk, if necessary, and
executed.
 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.
 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.
 Subprograms can be local.
 Local subprograms must be declared in the declarative section of PL/SQL block and
called from the executable section.
 Subprograms can not have the declarative section separately.
 Stored subprograms can have local subprograms;
 Local subprograms also can have local subprograms.
 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).
 Subprograms can be invalidated.
PROCEDURES V FUNCTIONS
 Procedures may return through out and in out parameters where as function must
return.
 Procedures can not have return clause where as functions must.
 We can use call statement directly for executing procedure where as we need to
declare a variable in case of functions.
 Functions can use in select statements where as procedures can not.
 Functions can call from reports environment where as procedures can not.
 We can use exec for executing procedures where as functions can not.
 Function can be used in dbms_output where as procedure can not.
 Procedure call is a standalone executable statement where as function call is a part of
an executable statement.
STORED V LOCAL SUBPROGRAMS

ORACLE
 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.
 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.
 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.
 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.
 Stand alone stored subprograms can not be overloaded, but packaged subprograms
can
be overloaded within the same package.
 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

ORACLE
BEGIN
dbms_output.put_line('Local subprogram');
END;
BEGIN
p;
END;
Output:
Local subprogram
COMPILING SUBPROGRAMS
 SQL> Alter procedure P1 compile;
 SQL> Alter function F1 compile;
SUBPROGRAMS DEPENDECIES
 A stored subprogram is marked as invalid in the data dictionary if it has compile
errors.
 A stored subprogram can also become invalid if a DDL operation is performed on one
of its dependent objects.
 If a subprogram is invalidated, the PL/SQL engine will automatically attempt to
recompile in the next time it is called.
 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
 We will call remote subprogram using connect string like P1@ORACLE;
 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.
 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.
 P1 and P2 are compared to see it P1 needs to be recompiled, there are two different
methods of comparision
 Timestamp Model

ORACLE
 Signature Model
TIMESTAMP MODEL
 This is the default model used by oracle.
 With this model, the timestamps of the last modifications of the two objects are
compared.
 The last_ddl_time field of user_objects contains the timestamp.
 If the base object has a newer timestamp than the dependent object, the dependent
object will be recompiled.
ISSUES WITH THIS MODEL
 If the objects are in different time zones, the comparison is invalid.
 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
 When a procedure is created, a signature is stored in the data dictionary in addition to
the p-code.
 The signature encodes the types and order of the parametes.
 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.
 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
 Add the line REMOTE_DEPENDENCIES_MODE=SIGNATURE to the database initialization file.
The next time the database is started, the mode will be set to SIGNATURE for all
sessions.
 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.
 Alter session set remote_dependencies_mode = signature;
This will only affect your session

ORACLE
ISSUES WITH THIS MODEL
 Signatures don’t get modified if the default values of formal parameters are changed.
 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.
 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
p3;
END P2;
PROCEDURE P3 IS
BEGIN
END P3;
BEGIN
p1;
END;

ORACLE
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
p2;
END P1;
PROCEDURE P2 IS
BEGIN
p3;
END P2;
PROCEDURE P3 IS
BEGIN
END P3;
BEGIN
p1;
END;
Output:
From procedure p1
From procedure p2
From procedure p3
PRIVILEGES AND STORED SUBPROGRAMS

ORACLE
EXECUTE PREVILEGE
 For stored subprograms and packages the relevant privilege is EXECUTE.
 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.
 Then user B can run the procedure by issuing
SQL> Exec user A.emp_proc
userA created the following procedure
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;
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
 Oracle introduces Invoker’s and Definer’s rights.
 By default it will use the definer’s rights.
 An invoker’s rights routine can be created by using AUTHID clause to populate the
userB’s table.
 It is valid for stand-alone subprograms, package specifications, and object type

ORACLE
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.

ORACLE
If the same privilege was granted through a role it wont create the procedure.
Examine the following code
SQL> conn saketh/saketh
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
 In an invoker’s rights routine, external references in SQL statements will be resolved
using the caller’s privilege set.
 But references in PL/SQL statements are still resolved under the owner’s privilege set.
TRIGGERS, VIEWS AND INVOKER’S RIGHTS
 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.
 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.

ORACLE
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
 The first time a packaged subprogram is called or any reference to a packaged
variable or type is made, the package is instantiated.
 Each session will have its own copy of packaged variables, ensuring that two sessions
executing subprograms in the same package use different memory locations.
 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.
 Packages are stored in the data dictionary and can not be local.
 Packaged subprograms has an advantage over stand alone subprogram.
 When ever any reference to package, the whole package p-code was stored in shared
pool of SGA.
 Package may have local subprograms.
 You can include authid clause inside the package spec not in the body.
 The execution section of a package is know as initialization section.

ORACLE
 You can have an exception section at the bottom of a package body.
 Packages subprograms are not invalidated.
COMPILING PACKAGES
 SQL> Alter package PKG compile;
 SQL> Alter package PKG compile specification;
 SQL> Alter package PKG compile body;
PACKAGE DEPENDENCIES
 The package body depends on the some objects and the package header.
 The package header does not depend on the package body, which is an advantage of
packages.
 We can change the package body with out changing the header.
PACKAGE RUNTIME STATE
Package runtime state is differ for the following packages.
 Serially reusable packages
 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 PKG IS
pragma serially_reusable;
procedure emp_proc;
END PKG;
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;

ORACLE
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
 The above package displays the same output for each execution even though the
cursor is not closed.
 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.

ORACLE
procedure emp_proc;
END PKG;
CREATE OR REPLACE PACKAGE BODY 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

ORACLE
 The above package displays the different output for each execution even though the
cursor is not closed.
 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;
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.

ORACLE
 The anonymous block depends on pkg. This is compile time dependency.
 There is also a runtime dependency on the packaged variables, since each session has
its own copy of packaged variables.
 Thus when pkg is recompiled the runtime dependency is followed, which invalidates
the block and raises the oracle error.
 Runtime dependencies exist only on package state. This includes variables and
cursors declared in a package.
 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.
 The function has to be stored in the database, either stand-alone or as part of a
package.
 The function can take only in parametes.
 The formal parameters must use only database types, not PL/SQL types such as
boolean
or record.
 The return type of the function must also be a database type.

ORACLE
 The function must not end the current transaction with commit or rollback, or rollback
to
a savepoint prior to the function execution.
 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;
FUNCTION FUN1 return varchar IS
BEGIN
update dept set deptno = 11;
return 'hello';
END FUN1;
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

ORACLE
BEGIN
return 'hello';
END FUN1;
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;
BEGIN
return 'hello';
END FUN1;
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.

ORACLE
BEGIN
return 'hello';
END FUN1;
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;
BEGIN
return 'hello';
END FUN1;
BEGIN
return 'hello';
END FUN2;
END PKG;
The above package will be created successfully.

ORACLE
IMPORTANT POINTS ABOUT RESTRICT_REFERENCES
 This pragma can appear anywhere in the package specification, after the function
declaration.
 It can apply to only one function definition.
 For overload functions, the pragma applies to the nearest definition prior to the
pragma.
 This pragma is required only for packages functions not for stand-alone functions.
 The Pragma can be declared only inside the package specification.
 The pragma is checked at compile time, not runtime.
 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
 KEEP
 UNKEEP
 SIZES
 ABORTED_REQUEST_THRESHOLD
KEEP
The DBMS_SHARED_POOL.KEEP procedure is used to pin objects in the pool.

ORACLE
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.

ORACLE
Syntax:
PROCEDURE ABORTED_REQUEST_THRESHOLD(threshold_size 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
 USER_OBJECTS
 USER_SOURCE
 USER_ERRORS
 DBA_OBJECTS
 DBA_SOURCE
 DBA_ERRORS
 ALL_OBJECTS
 ALL_SOURCE
 ALL_ERRORS

ORACLE
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
 Header
 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
 Implicit (SQL)
 Explicit
 Parameterized cursors
 REF cursors
CURSOR STAGES
 Open
 Fetch
 Close
CURSOR ATTRIBUTES
 %found

ORACLE
 %notfound
 %rowcount
 %isopen
 %bulk_rowcount
 %bulk_exceptions
CURSOR DECLERATION
Syntax:
Cursor <cursor_name> is select statement;
Ex:
Cursor c is select *from dept;
CURSOR LOOPS
 Simple loop
 While loop
 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);

ORACLE
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
end loop;
close c;
END;
Output:
Name = saketh
Name = srinu
Name = satish
Name = sudha
FOR LOOP
Syntax:

ORACLE
for <record_variable> in <cursor_name> loop
<statements>;
End loop;
Ex:
DECLARE
BEGIN
for v_stud in c loop
end loop;
END;
Output:
Name = saketh
Name = srinu
Name = satish
Name = sudha
PARAMETARIZED CURSORS
 This was used when you are going to use the cursor in more than one place with
different values for the same where clause.
 Cursor parameters must be in mode.
 Cursor parameters may have default values.
 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;

ORACLE
END;
Output:
Dname = RESEARCH Loc = DALLAS
PACKAGED CURSORS WITH HEADER IN SPEC AND BODY IN PACKAGE BODY
 cursors declared in packages will not close automatically.
 In packaged cursors you can modify the select statement without making any
changes to the cursor header in the package specification.
 Packaged cursors with must be defined in the package body itself, and then use it as
global for the package.
 You can not define the packaged cursor in any subprograms.
 Cursor declaration in package with out body needs the return clause.
Ex:
cursor c return dept%rowtype is select * from dept;
procedure proc is
END PKG;
CREATE OR REPLACE PAKCAGE BODY PKG IS
cursor c return dept%rowtype 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
CREATE OR REPLACE PAKCAGE BODY PKG IS

ORACLE
cursor c return dept%rowtype 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
REF CURSORS AND CURSOR VARIABLES
 This is unconstrained cursor which will return different types depends upon the user
input.
 Ref cursors can not be closed implicitly.
 Ref cursor with return type is called strong cursor.
 Ref cursor with out return type is called weak cursor.
 You can declare ref cursor type in package spec as well as body.
 You can declare ref cursor types in local subprograms or anonymous blocks.
 Cursor variables can be assigned from one to another.
 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.
 Cursor variables can be passed as a parameters to the subprograms.
 Cursor variables modes are in or out or in out.
 Cursor variables can not be declared in package spec and package body (excluding
subprograms).
 You can not user remote procedure calls to pass cursor variables from one server to
another.
 Cursor variables can not use for update clause.
 You can not assign nulls to cursor variables.
 You can not compare cursor variables for equality, inequality and nullity.

ORACLE
Ex:
CREATE OR REPLACE PROCEDURE 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.dname || ' 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
dbms_output.put_line('Name = ' || v_stud);
end if;
end loop;
close c;
END;
Output:
SQL> exec ref_cursor('DEPT')

ORACLE
Deptno = 10 Dname = ACCOUNTING Loc = NEW YORK
Deptno = 20 Dname = RESEARCH Loc = DALLAS
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
 You can use cursor expressions in explicit cursors.
 You can use cursor expressions in dynamic SQL.
 You can use cursor expressions in REF cursor declarations and variables.
 You can not use cursor expressions in implicit cursors.
 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.

ORACLE
 Nested cursor closes if you close explicitly.
 Nested cursor closes whenever the outer or parent cursor is executed again or closed
or canceled.
 Nested cursor closes whenever an exception is raised while fetching data from a
parent cursor.
 Cursor expressions can not be used when declaring a view.
 Cursor expressions can be used as an argument to table function.
 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
 Return
 For update
 Where current of

ORACLE
 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:

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

ORACLE
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
end loop;
END;
Output:
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;

ORACLE
Close c;
end loop;
END;
Output:
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('Dname = ' || 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

ORACLE
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
dbms_output.put_line('Dname = ' || 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;

ORACLE
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
 Cursor name can be up to 30 characters in length.
 Cursors declared in anonymous blocks or subprograms closes automatically when that
block terminates execution.
 %bulk_rowcount and %bulk_exceptions can be used only with forall construct.
 Cursor declarations may have expressions with column aliases.
 These expressions are called virtual columns or calculated columns.

ORACLE
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
 Early binding
 Late binding
 Binding during the compiled phase is early binding.
 Binding during the runtime phase is late binding.
 In early binding compile phase will take longer because of binding work but the
execution
is faster.
 In late binding it will shorten the compile phase but lengthens the execution time.
 PL/SQL by default uses early binding.
 Binding also involves checking the database for permissions to access the object
Referenced.
DYNAMIC SQL
 If you use DDL in pl/sql it validates the permissions and existence if requires during
compile time which makes invalid.
 We can avoid this by using Dynamic SQL.
 Dynamic SQL allows you to create a SQL statement dynamically at runtime.
Two techniques are available for Dynamic SQL.
 Native Dynamic SQL
 DBMS_SQL package
USING NATIVE DYNAMIC SQL

ORACLE
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;

ORACLE
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

ORACLE
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

ORACLE
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);
dbms_output.put_line('No = ' || sreturn.name);
dbms_output.put_line('No = ' || sreturn.marks);
END;
Output:
No = 8

ORACLE
No = dd
No = 500
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
Ex:
DECLARE
ibt t;
type t1 is table of boolean index by binary_integer;
ibt1 t1;
BEGIN

ORACLE
ibt(1) := 1;
ibt(10) := 2;
ibt(100) := 3;
ibt1(1) := true;
ibt1(10) := true;
ibt1(100) := true;
forall i in indices of ibt1
END;
USGAGE OF INDICES OF TO AVOID THE ABOVE BEHAVIOUR
Ex:
DECLARE
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
END;
POINTS ABOUT BULK BINDS
 Passing the entire PL/SQL table to the SQL engine in one step is known as bulk bind.
 Bulk binds are done using the forall statement.
 If there is an error processing one of the rows in bulk DML operation, only that row
is rolled back.
POINTS ABOUT RETURING CLAUSE
 This will be used only with DML statements to return data into PL/SQL variables.

ORACLE
 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.
 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
 Varrays
 Nested tables
 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));

ORACLE
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
end if;
if flag = true then
else
end if;
va.extend(2);
dbms_output.put_line('After extend of two indexes, Count = ' || va.count);
end loop;
va(5) := 'e';
va(6) := 'f';
va(7) := 'g';
dbms_output.put_line('AFTER ASSINGNING VALUES TO EXTENDED ELEMENTS,
VARRAY ELEMENTS');
end loop;
va.extend(3,2);
dbms_output.put_line('After extend of three indexes, Count = ' || va.count);

ORACLE
end loop;
va.trim;
dbms_output.put_line('After trim of one index, Count = ' || va.count);
va.trim(3);
dbms_output.put_line('After trim of three indexs, Count = ' || va.count);
dbms_output.put_line('AFTER TRIM, VARRAY ELEMENTS');
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] =

ORACLE
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;

ORACLE
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:

ORACLE
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;

ORACLE
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
dbms_output.put_line('Limit = ' || nt.limit);
end if;
dbms_output.put_line('Count = ' || nt.count);
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));
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
dbms_output.put_line('Index 3 exists with an element ' || nt(3));

ORACLE
else
end if;
nt.extend;
dbms_output.put_line('After extend of one index, Count = ' || nt.count);
if flag = true then
else
end if;
if flag = true then
else
end if;
nt.extend(2);
dbms_output.put_line('After extend of two indexes, Count = ' || nt.count);
end loop;
nt(5) := 'e';
nt(6) := 'f';
nt(7) := 'g';
dbms_output.put_line('AFTER ASSINGNING VALUES TO EXTENDED ELEMENTS, NESTED TABLE
ELEMENTS');
end loop;
nt.extend(5,2);
dbms_output.put_line('After extend of five indexes, Count = ' || nt.count);
end loop;
nt.trim;

ORACLE
dbms_output.put_line('After trim of one index, Count = ' || nt.count);
nt.trim(3);
dbms_output.put_line('After trim of three indexs, Count = ' || nt.count);
dbms_output.put_line('AFTER TRIM, NESTED TABLE ELEMENTS');
end loop;
nt.delete(1);
dbms_output.put_line('After delete of first index, Count = ' || nt.count);
for i in 2..nt.count+1 loop
end loop;
nt.delete(4);
dbms_output.put_line('After delete of fourth index, Count = ' || nt.count);
for i in 2..3 loop
end loop;
for i in 5..nt.count+2 loop
end loop;
nt.delete;
dbms_output.put_line('After delete of 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

ORACLE
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

ORACLE
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;

ORACLE
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 student where sno = i;
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 student where sno = i;
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

ORACLE
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:

ORACLE
nt1 is null
nt2 is not null
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
dbms_output.put_line('No limit to Index by Tables');
else
dbms_output.put_line('Limit = ' || ibt.limit);
end if;
dbms_output.put_line('Count = ' || ibt.count);
dbms_output.put_line('First Index = ' || ibt.first);
dbms_output.put_line('Last Index = ' || ibt.last);
dbms_output.put_line('Next Index = ' || ibt.next(2));
dbms_output.put_line('Previous Index = ' || 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));
flag := ibt.exists(30);
if flag = true then
dbms_output.put_line('Index 30 exists with an element ' || ibt(30));

ORACLE
else
end if;
if flag = true then
dbms_output.put_line('Index 50 exists with an element ' || ibt(30));
else
end if;
ibt.delete(1);
dbms_output.put_line('After delete of first index, Count = ' || ibt.count);
ibt.delete(30);
dbms_output.put_line('After delete of index thirty, Count = ' || ibt.count);
dbms_output.put_line('INDEX BY TABLE ELEMENTS');
dbms_output.put_line('ibt[-20] = ' || ibt(-20));
ibt.delete;
dbms_output.put_line('After delete of 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

ORACLE
ibt[-20] = b
ibt[100] = d
After delete of entire index-by table, Count = 0
DIFFERENCES AMONG COLLECTIONS
 Varrays has limit, nested tables and index-by tables has no limit.
 Varrays and nested tables must be initialized before assignment of elements, in
index-by tables we can directly assign elements.
 Varrays and nested tables stored in database, but index-by tables can not.
 Nested tables and index-by tables are PL/SQL tables, but varrays can not.
 Keys must be positive in case of nested tables and varrays, in case of index-by tables
keys can be positive or negative.
 Referencing nonexistent elements raises SUBSCRIPT_BEYOND_COUNT in both nested tables
and varrays, but in case of index-by tables NO_DATA_FOUND raises.
 Keys are sequential in both nested tables and varrays, non-sequential in index-by
tables.
 Individual indexes can be deleted in both nested tables and index-by tables, but in
varrays can not.
 Individual indexes can be trimmed in both nested tables and varrays, but in index-by
tables can not.
 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();

ORACLE
c number := 97;
flag boolean;
BEGIN
va.extend(4);
dbms_output.put_line('Count = ' || va.count);
dbms_output.put_line('Limit = ' || va.limit);
for j in 1..va.count loop
va(i)(j) := chr(c);
c := c + 1;
end loop;
end loop;
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
dbms_output.put_line('Index 2 exists');
else
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';

ORACLE
dbms_output.put_line('After extend of one index, Count = ' || va.count);
end loop;
end loop;
va.trim;
dbms_output.put_line('After trim of one index, Count = ' || va.count);
va.trim(2);
dbms_output.put_line('After trim of two indexes, Count = ' || va.count);
end loop;
end loop;
va.delete;
dbms_output.put_line('After delete of 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

ORACLE
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

ORACLE
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
type t2 is table of t1;
nt t2 := t2();
c number := 65;
v number := 1;
flag boolean;
BEGIN
nt.extend(4);
if nt.limit is null then
dbms_output.put_line('No limit to Nested Tables');
else
dbms_output.put_line('Limit = ' || 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;
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);

ORACLE
dbms_output.put_line('Next index = ' || nt.next(2));
dbms_output.put_line('Previous index = ' || nt.prior(3));
if flag = true then
else
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';
dbms_output.put_line('After extend of one index, Count = ' || nt.count);
end loop;
end loop;
nt.trim;
dbms_output.put_line('After trim of one indexe, Count = ' || nt.count);

ORACLE
nt.trim(2);
dbms_output.put_line('After trim of two indexes, Count = ' || nt.count);
end loop;
end loop;
nt.delete(2);
dbms_output.put_line('After delete of second index, Count = ' || nt.count);
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;
dbms_output.put_line('After delete of 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

ORACLE
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

ORACLE
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
type t2 is table of t1 index by binary_integer;

ORACLE
ibt t2;
flag boolean;
BEGIN
if ibt.limit is null then
dbms_output.put_line('No limit to Index-by Tables');
else
dbms_output.put_line('Limit = ' || 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));
dbms_output.put_line('First Index = ' || ibt.first);
dbms_output.put_line('Last Index = ' || ibt.last);
dbms_output.put_line('Next Index = ' || 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';
for i in 1..8 loop
dbms_output.put_line('ibt[1][' || i || '] = ' || ibt(1)(i));
end loop;

ORACLE
if flag = true then
else
end if;
ibt.delete(1);
dbms_output.put_line('After delete of first index, Count = ' || ibt.count);
ibt.delete(4);
dbms_output.put_line('After delete of fourth index, Count = ' || ibt.count);
ibt.delete;
dbms_output.put_line('After delete of 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

ORACLE
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
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);
for k in 1..nt.count loop

ORACLE
nt(i)(j)(k) := chr(c);
c := c + 1;
end loop;
end loop;
end loop;
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

ORACLE
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')

ORACLE
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
 Compile-time errors
 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

ORACLE
 Predefined exceptions
 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('Invalid student number');
END;
-- CURSOR_ALREADY_OPEN
BEGIN
open c;
open c;
EXCEPTION
when cursor_already_open then
dbms_output.put_line('Cursor is already opened');
END;
-- INVALID_CURSOR
BEGIN
close c;
open c;
close c;

ORACLE
close c;
EXCEPTION
when invalid_cursor then
dbms_output.put_line('Cursor 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('Too many values are coming to marks
variable');
END;
-- ZERO_DIVIDE
BEGIN
a := 5/0;
EXCEPTION
when zero_divide then
dbms_output.put_line('Divided by zero - invalid operation');
END;
-- VALUE_ERROR
BEGIN
b := 'saketh';
EXCEPTION
when value_error then
dbms_output.put_line('Invalid string length');
END;
-- INVALID_NUMBER
BEGIN
insert into student values('a','srinu',100);
EXCEPTION
when invalid_number then
dbms_output.put_line('Invalid number');
END;
-- SUBSCRIPT_OUTSIDE_LIMIT
BEGIN
va(4) := 'c';
EXCEPTION
when subscript_outside_limit then
dbms_output.put_line('Index is greater than the limit');
END;
-- SUBSCRIPT_BEYOND_COUNT
BEGIN

ORACLE
va(3) := 'c';
EXCEPTION
when subscript_beyond_count then
dbms_output.put_line('Index is greater than the count');
END;
-- COLLECTION_IS_NULL
BEGIN
va1(1) := 'a';
EXCEPTION
when collection_is_null then
dbms_output.put_line('Collection 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('Invalid Operation');
when others then
dbms_output.put_line('From OTHERS handler: Invalid Operation');
END;
Output:

ORACLE
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
SQLCODE returns the current error code, and SQLERRM returns the current error message text;
For user-defined exception SQLCODE returns 1 and SQLERRM returns “user-deifned exception”.
SQLERRM wiil take only negative value except 100. If any positive value other than 100
returns non-oracle exception.
Ex1:
DECLARE
e exception;

ORACLE
v_dname varchar(10);
BEGIN
-- USER-DEFINED EXCEPTION
BEGIN
raise e;
EXCEPTION
when e then
dbms_output.put_line(SQLCODE || ' ' || 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(SQLCODE || ' ' || SQLERRM);
END;
END;
Output:
1 User-Defined Exception
100 ORA-01403: no data found
Ex2:
BEGIN
dbms_output.put_line(SQLERRM(100));
dbms_output.put_line(SQLERRM(-100));
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

ORACLE
ORA-00900: invalid SQL statement
DBMS_UTILITY.FORMAT_ERROR_STACK
The built-in function, like SQLERRM, returns the message associated with the current error.
It differs from SQLERRM in two ways:
Its length is not restricted; it will return the full error message string.
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;

ORACLE
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
p1;
END P2;
BEGIN
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

ORACLE
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('Invalid 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

ORACLE
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
END;
Output:
e is raised
Ex2:

ORACLE
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
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

ORACLE
END;
EXCEPTION
when others then
dbms_output.put_line('From 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
END;
Output:
e1 is raised
DECLARE
*
ERROR at line 1:
Ex2:
DECLARE
e1 exception;
e2 exception;BEGIN

ORACLE
BEGIN
raise e1;
EXCEPTION
when e1 then
raise e2;
when e2 then
END;
EXCEPTION
when e2 then
dbms_output.put_line('From 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
raise e;
END;
Output:
e is raised
DECLARE
*
ERROR at line 1:
RESTRICTIONS
You can not pass exception as an argument to a subprogram.

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

ORACLE
Statement level trigger fires once either before or after the statement.
DML TRIGGER SYNTAX
Create or replace trigger <trigger_name>
Before | after on insert or update or delete
[For each row]
Begin
-- trigger body
End <trigger_name>;
DML TRIGGERS
A DML trigger is fired on an INSERT, UPDATE, or DELETE 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).
ORDER OF DML TRIGGER FIRING
 Before statement level
 Before row level
 After row level
 After statement level
Ex:
Suppose we have a follwing table.
NO NAME MARKS
----- ------- ----------
1 a 100
2 b 200

ORACLE
3 c 300
4 d 400
Also we have triggering_firing_order table with firing_order as the field.
CREATE OR REPLACE TRIGGER TRIGGER1
before insert on student
BEGIN
insert into trigger_firing_order values('Before Statement Level');
END TRIGGER1;
before insert on student
for each row
BEGIN
insert into trigger_firing_order values('Before Row Level');
END TRIGGER2;
after insert on student
BEGIN
insert into trigger_firing_order values('After Statement Level');
END TRIGGER3;
after insert on student
for each row
BEGIN
insert into trigger_firing_order values('After Row Level');
END TRIGGER4;
Output:
SQL> select * from trigger_firing_order;
no rows selected
SQL> insert into student values(5,'e',500);
1 row created.
SQL> select * from trigger_firing_order;

ORACLE
FIRING_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.

ORACLE
update.
DELETE original values before all fields are NULL.
the row is deleted.
Ex:
Suppose we have a table called marks with fields no, old_marks, new_marks.
CREATE OR REPLACE TRIGGER 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
SQL> insert into student values(6,'f',600);
1 row created.
NO NAME MARKS
---- -------- ----------
1 a 100
2 b 200

ORACLE
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
SQL> delete student where no = 2;
1 row deleted.

ORACLE
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:
CREATE OR REPLACE TRIGGER REFERENCE_TRIGGER
referencing old as old_student new as new_student
for each row
BEGIN
insert into marks
values(:old_student.no,:old_student.marks,: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:

ORACLE
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:
CREATE OR REPLACE TRIGGER WHEN_TRIGGER
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.marks,: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
 INSERTING
 UPDATING
 DELETING
Ex:
CREATE OR REPLACE TRIGGER PREDICATE_TRIGGER
BEGIN
if inserting then
insert into predicates values('I');
elsif updating then
insert into predicates values('U');
elsif deleting then
insert into predicates values('D');
end if;
END PREDICATE_TRIGGER;

ORACLE
Output:
SQL> delete student where no=1;
1 row deleted.
SQL> select * from predicates;
MSG
---------------
D
SQL> insert into student values(7,'g',700);
1 row created.
MSG
---------------
D
I
SQL> update student set marks = 777 where no=7;
1 row updated.
MSG
---------------
D
I
U

ORACLE
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:
 To allow a view that would otherwise not be modifiable to be modified.
 To modify the columns of a nested table column in a view.
Thank You……………………..
Happy Learning......

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