ora_sothea

Course Objectives After completing this course, you should be able to do the following: Install, create, and administer Oracle Database 10 g Understand Oracle SQL and PL/SQL Configure the database for an application Create and Configure Oracle Distributed Database Can Perform Backup, Restore and Recover Database

Lesson Objectives After completing this lesson, you should be able to do the following: Explain the Oracle Database architecture

Oracle Products and Services Oracle databases Oracle Application Server Oracle applications Oracle Collaboration Suite Oracle Developer Suite Oracle services

Oracle Database Architecture An Oracle server: Is a database management system that provides an open, comprehensive, integrated approach to information management Consists of an Oracle Service , Oracle instance and an Oracle database

Database Structures Storage structures Memory structures Process structures Instance Database files DB structures - Memory - Process - Storage Oracle Service System Global Area (SGA) Background processes

Oracle Memory Structures . Database buffer cache Redo log buffer Shared pool Large pool SGA Streams pool Server process 1 PGA Server process 2 PGA Background process PGA DB structures > Memory Process Storage

Process Structures User process: Is started at the time a database user requests a connection to the Oracle server Server process: Connects to the Oracle instance and is started when a user establishes a session Background processes: Are started when an Oracle instance is started Instance Background processes Server process PGA User process DB structures Memory > Process Storage SGA

Oracle Instance Management System Monitor (SMON) Database Writer (DBW n ) LogWriter (LGWR) Process Monitor (PMON) Archiver (ARC n ) SGA Java pool Shared pool Large pool Streams pool Database buffer cache Redo log buffer Checkpoint (CKPT) Control files Data files Redo log files Archive log files

Server Process and Database Buffer Cache Buffers: Pinned Clean Free or unused Dirty Server process SGA Database buffer cache Data files DBW n

Physical Database Structure . Online redo log files Password file Parameter file Archive log files Control files Data files Alert and trace log files Backup files DB structures Memory Process > Storage

Tablespaces and Data Files Tablespaces consist of one or more data files. Data files belong to only one tablespace. Data file 1 Data file 2 USERS tablespace

SYSTEM and SYSAUX Tablespaces The SYSTEM and SYSAUX tablespaces are mandatory tablespaces. They are created at the time of database creation. They must be online. The SYSTEM tablespace is used for core functionality (for example, data dictionary tables). The auxiliary SYSAUX tablespace is used for additional database components (such as the Enterprise Manager Repository).

Segments, Extents, and Blocks Segments exist within a tablespace. Segments are made up of a collection of extents. Extents are a collection of data blocks. Data blocks are mapped to disk blocks. Segment Extents Data blocks Disk blocks

Logical and Physical Database Structures Database Logical Physical Tablespace Data file OS block Segment Extent Oracle data block Schema

Course Examples: The HR Schema REGIONS REGION_ID (PK) REGION_NAME COUNTRIES COUNTRY_ID (PK) COUNTRY_NAME REGION_ID (FK) LOCATIONS LOCATION_ID (PK) STREET_ADDRESS POSTAL_CODE CITY STATE_PROVINCE COUNTRY_ID (FK) DEPARTMENTS DEPARTMENT_ID (PK) DEPARTMENT_NAME MANAGER_ID LOCATION_ID (FK) JOBS JOB_ID (PK) JOB_TITLE MIN_SALARY MAX_SALARY EMPLOYEES EMPLOYEE_ID (PK) FIRST_NAME LAST_NAME EMAIL PHONE_NUMBER HIRE_DATE JOB_ID (FK) SALARY COMMISION_PCT MANAGER_ID (FK) DEPARTMENT_ID (FK) JOB_HISTORY EMPLOYEE_ID (PK) START_DATE (PK) END_DATE JOB_ID (FK) DEPARTMENT_ID (FK) REGIONS COUNTRIES LOCATIONS DEPARTMENTS JOBS EMPLOYEES JOB_HISTORY

Database Architecture: Summary of Structural Components Database Service Memory structures: System Global Area (SGA): Database buffer cache, redo buffer, and various pools Program Global Area (PGA) Process structures: User process and Server process Background processes: SMON, PMON, DBW n , CKPT, LGWR, ARC n , and so on Storage structures: Logical: Database, schema, tablespace, segment, extent, and Oracle block Physical: Files for data, parameters, redo, and OS block

Summary In this lesson, you should have learned how to: Install, create, and administer Oracle Database 10 g Configure the database for an application Employ basic monitoring procedures Implement a backup and recovery strategy Move data between databases and files

Installing the Oracle Database Software Chapter 2

Objectives After completing this lesson, you should be able to do the following: Describe your role as a database administrator (DBA), and explain typical tasks and tools Plan an Oracle database installation Use Optimal Flexible Architecture (OFA) Install the Oracle software by using Oracle Universal Installer (OUI)

Tasks of an Oracle Database Administrator A prioritized approach for designing, implementing, and maintaining an Oracle database involves the following tasks: 1. Evaluating the database server hardware 2. Installing the Oracle software 3. Planning the database and security strategy 4. Creating, migrating, and opening the database 5. Backing up the database 6. Enrolling system users and planning for their Oracle Network access 7. Implementing the database design 8. Recovering from database failure 9. Monitoring database performance

Tools Used to Administer an Oracle Database Oracle Universal Installer Database Configuration Assistant Database Upgrade Assistant Oracle Net Manager Oracle Enterprise Manager SQL*Plus and i SQL*Plus Recovery Manager Oracle Secure Backup Data Pump SQL*Loader Command-line tools

Installation: System Requirements Memory requirements: 1 GB for the instance with Database Control Disk space requirements: 1.5 GB of swap space 400 MB of disk space in the /tmp directory Between 1.5 GB and 3.5 GB for the Oracle software 1.2 GB for the preconfigured database (optional) 2.4 GB for the flash recovery area (optional) Operating system: See documentation.

Checking the System Requirements Adequate temporary space 64-bit versus 32-bit issues Checks for the correct operating system (OS) System and kernel parameters ORACLE_HOME

Optimal Flexible Architecture (OFA) OFA is designed to: Organize large amounts of software Facilitate routine administrative tasks Manage and administer database growth adequately Help eliminate fragmentation of free space

Using Optimal Flexible Architecture Naming mount points: /u01 /disk01 Naming directories: /u01/app/oracle /u01/app/applmgr Naming files: Control files: control n .ctl Redo log files: redo n .log Data files: tn .dbf

Setting Environment Variables ORACLE_HOME : The directory containing the Oracle software ORACLE_SID : The initial instance name (by default, ORCL ) NLS_LANG : The language, territory, and client character set settings

Oracle Universal Installer (OUI)

Database Configuration Options

Creating an Oracle Database Chapter 3

Objectives After completing this lesson, you should be able to do the following: Create a database with the Database Configuration Assistant (DBCA) Create a database design template with the DBCA Generate database creation scripts with the DBCA

Planning the Database As a DBA, you must plan: The logical storage structure of the database and its physical implementation: How many disk drives do you have for this? How many data files will you need? (Plan for growth.) How many tablespaces will you use? Which type of information will be stored? Are there any special storage requirements due to type or size? The overall database design A backup strategy for the database

Databases: Examples Data Warehouse: Research and marketing data State or federal tax payments Professional licensing (doctors, nurses, and so on) Transaction Processing: Store checkout register system Automatic teller machine (ATM) transactions General Purpose: Retail billing system, for example, of a software house or a general database.

Database Configuration Assistant (DBCA)

Using the DBCA to Create a Database

Using the DBCA to Create a Database 3 4

Using the DBCA to Create a Database 5 6 7

Using the DBCA to Create a Database A B 10

Creating a Database Design Template

Using the DBCA to Delete a Database 1 2 3

Summary In this lesson, you should have learned how to use the DBCA to: Create a database Create a database design template Generate database creation scripts

Practice Overview: Using the DBCA This practice covers the following topics : Creating the ORCL database by using the DBCA Unlocking the HR schema Note: Completing the database creation and unlocking the HR schema is critical for all following practice sessions. Optionally: Creating the ORCL database design template by using the DBCA Creating database creation scripts with the DBCA

Creating Database by Manual Component: Configure Parameter File or Init File Create Database Service Startup Instance Create Database Setup System Database Create Database Storage Configure oracle network Create Database Objects

Create Init File Parameter File or Init File is an text file contains parameters use to configure Database Instance while it is started up. Parameters are consist of: DB_NAME =Specific name of the instance(Database) Control_file s=(Specific location and name of control file) Undo_Management =Define how to management transaction auto or by rollback segment Undo_Tablespace =Name of Tablespace to keep transaction. Processes =Number of Process allow Sessions =number of current connection DB_Block_Size =Size of unit write or read data into file.

Create Database Service Oracle Database Service: is an identifier of database on network environment. It’s a service provider to clients whom whish to connect to oracle server to get service. Syntax: On DOS Prompt OraDim –NEW –SID nameofservice [-SYSPWD internal password –START MODE Auto|Manual - PFILE ‘Path\Parameter file name’]

Syntax Delete: Oradim –Delete –SID nameofservice

Connect to Oracle Service and Create Instance: To Create Database Instance (In-Memory Database) - Specific Oracle service (SID) SET ORACLE_SID=Oracle Service Name - Go into Oracle Utility call SQL PLUS with nolog option SQLPLUS/NOLOG Connect to specific service(SID) by database administrator CONNECT / AS SYSDBA - Startup Database Instance with nomount option STARTUP NOMOUNT [PFILE=Path\Parameter File Name]

Create Database File and Open Database Instance

Setup System For oracle 10g and above must be configure SysAux Datafile @%Oracle_home%\rdbms\admin\catalog Install database catalog and dynamic view @%Oracle_home%\rdbms\admin\catproc Install PL/SQL Compiler and oracle pre-define functions and packages.

Create Tablespace (Storage) An tablespace is a pointer of data files on database instance. There are following type of tablespace. - System: Store system database objects - System Auxiliary: store system object support to system tablespace (this tablespace unavailable for oracle 9i or below. - Temporary tablespace: use to store query data such join, sort. - Undo Tablespace: This tablespace use transaction. - User Tablespace: Store user input data(tables) - Index Tablespace: Store index.

Create Tablespace: Create [undo] Tablespace Name-Of-Tablespace Datafile ‘path\filename’ size initialSize [Temporary] [Auto extend on [Next Size IncrementalSize] MaxSize MaximumDatafile;

Create net service Net Service is representative of Oracle Service in client computer, it’s used to connect to oracle server by application. Without netservice Application could not connect to Oracle. To create netservice - Open “Net Manager” - Select “Service Naming” - Click “Edit\Create” - Complete parameters as following -Net Service Name: use for connecting -Host Name: Computer Server Name(PC NAME) -Protocol (Keep Default TCP) and Port Number (Keep default 1521) -Oracle Service: Oracle Service Name

Connect to database On Dos: SQLPLUS Username/password@netservicename On SQLPLUS Connect Username/password@netservicename Net Service Name

Startup and Shutdown Server Startup Oracle Server: is a process to create oracle instance. Startup: - Start oracle service - Connect to oracle service by dba (database administrator) - Set Oracle_SID= OracleServiceName - SQL/NOLOG - Connect / as SysDBA - Startup Database Startup [Option] Pfile= ‘Path\ParameterFile’ Option: Nomount: Start for creating database Mount: Start for reconfiguring database Open: Start for working and providing service.

Shutdown Oracle Server Shutdown Oracle Server is process to close oracle server Connect to oracle server as sysdba Shutdown Shutdown [Option] Option Normal : Normally shutdown by let user disconnect oracle server by themselves. Transactional: Wait until user save transaction then server disconnect user and shutdown instance when disconnect all user. Immediate: Rollback all transaction and shutdown instance. Abort: Shutdown instance without manage every thing. Check “ Startup instance when instance is started”

Configure Oracle Server to Startup Auto To let oracle server to startup automatically when Window is Started: - Configure Oracle Service to start automatic - Connect Parameter File: Name:InitDBNAME.ORA FOLDER: Oracle_HOME\Database (D:\oracle\product\10.1.0\db_2\database) - Open program “Administration Assistant for Window” - Select “Database\DatabaseName” Right Click-> Startup/Shutdown Option

Configure Transactional - Shutdown Server. Open Parameter File -Add Command Undo_Management=Auto Undo_Tablespace=TablespaceName

Creating Oracle Database Objects Chapter 4

Oracle Objects Objectives: Using Data Definition Language to create: Table Index Sequence View Synonym To Create object: - Start Oracle Database Server - Connect to Oracle by User “System” - Write SQL Script: - Run Script:

Creating a Table Oracle Data Type String Char Size Varchar 4000 Varchar2 4000 NChar 2000 NVarchar2 2000 Long 2GB Number Number(N,P) Integer Float Binary BLOB 4GB DateTime Date

TABLE statement is as follows: CREATE Table Schema. table_name ( column_name type [CONSTRAINT constraint_def DEFAULT default_exp ] [, column_name type [CONSTRAINT constraint_def DEFAULT default_exp ]...] ) [TABLESPACE tab_space Storage];

Schema: Name of user to store object: Tablespace: Name of Tablespace where table is located. Storage option define extends and segment to store table’s data

Constraints Are condition of column: Primary Key: Foreign Key: Unique: Do not duplicate value Check: Set Condition for column Not Null:

Index An index is object store address of records. It’s use to retrieve record when it’s selected. Syntax: Create Index Name-Of-Index On Table_Name(ColumnName,..) Tablespace Name-of-Tablespace. Guideline: Index set on unique column or less duplicate Index set on columns use in where condition

View View: is virtual table to view data from tables. Syntax: Create View Name-of-View[(Col1,Col2,…)] AS Select SQL Statement.

Sequence: Is object use to generate autonumber. Syntax: Create Sequence Name-Of-Sequence [Increment By Step] [Start With StartNumber] Attribute of Sequence .NextVal: .CurrVal:

Synonym Is Object reference to another object: Syntax: Create [public] Synonym Name-Of-Synonym for [Schema.]ObjectName

System View use to check: DBA_Tablespaces: Store tablespace information of Server. User_Tablespaces: Similar DBA_Tablespaces store for current schema. User_Tables,DBA_Tables: DBA_Indexes,User_Indexes DBA_Views,User_Views DBA_Sequences,User_Sequences *** General form: USER_ObjectTypes Check Structure tables or views DESC Table-Name

Structured Query Language (SQL) Chapter 5

Agenda Keyword IN and BETWEEN Dual ????? FUNCTIONS Aggregate Numeric String Date Group By Having

Keywords IN & BETWEEN IN SELECT columns FROM tables WHERE column1 in (value1, value2, .... value_n); e.g. Select name from employee where desig IN(‘Manager’, ‘Clerk’, ‘Worker’); BETWEEN SELECT columns FROM tables WHERE column1 between value1 and value2; e.g. Select name from Employee where salary between 4500 AND 7000;

What is DUAL??? The DUAL table is a real table. It’s owned by the user SYS and has one row. The table has only one column, which is named DUMMY and has a string with a length of 1. The value of DUMMY in the one and only row is X. Note: Anyone can create a table like this, with one row, and accomplish the same thing. But it’s good practice to have one place where you always have one row and you always know the table name.

Aggregate Functions AVG MAX MIN COUNT SUM CORR VARIANCE STDDEV…

Aggregate Functions… Select count(*) from Employee; Select Count(Distinct(city)) from Employee; SELECT SUM(salary) as "Total Salary“ FROM employees where salary > 25000; SELECT SUM(sales * 0.10) as "Commission“ FROM order_details; SELECT MIN(salary) as "Lowest salary“ FROM employees; SELECT MAX(salary) as "Highest salary“ FROM employees; SELECT Avg(salary) as "Avg Salary“ FROM employees WHERE salary > 25000; SELECT Avg(sales * 0.10) as "Average Commission“ FROM orders; select stddev(salary) from employee;

Numeric Function ABS ACOS BITAND CEIL COS COSH EXP FLOOR LN MOD NANVL POWER ROUND SIGN SIN SQRT TAN LEAST GREATEST

Numeric Function… Select abs(23.65) from dual; Select abs( 12.34 * -2) from dual; Select bitand(6,2) from dual; Select acos(0.35) from dual; Select ceil(32.65) from dual; would return 33. Select ceil(-32.65) from dual; would return -32 Select floor(32.65) from dual; would return 32. Select floor(-32.65) from dual; would return -33 Select exp(3) from dual; Select ln(20) from dual;

Numeric Function… Select greatest(2, 5, 12, 3) from dual; would return 12 Select greatest('2', '5', '12', '3') from dual; would return '5' Select greatest('apples', 'oranges', 'bananas') from dual; Select least(2, 5, 12, 3) from dual; would return 2 Select least ('2', '5', '12', '3') from dual; would return ‘12‘ Select least ('apples', 'oranges', 'bananas') from dual; Select mod(15, 4) from dual; Select power(3, 2) from dual; Select sqrt(5.617) from dual; Select sign(-0.675) from dual; would give -1 Select sign(0) from dual; would give 0 Select sign(7.0001) from dual; would give 1

String Function TRIM LTRIM RTRIM ASCII CHR LPAD RPAD CONCAT INSTR INITCAP LENGTH LOWER UPPER REPLACE SUBSTR

String Function… TRIM( [ leading | trailing | both [ trim_character* ] ] string1 ) select TRIM('A' from 'AABABAB4AAA') from dual; select TRIM(LEADING 'A' from 'AABABAB4AAA') from dual; select TRIM(TRAILING 'A' from 'AABABAB4AAA') from dual; select TRIM(BOTH 'A' from 'AABABAB4AAA') from dual; CONCAT(string1, string2) select concat('a','b') from dual; Select ‘a’ || ‘b’ from dual;

String Function… LPAD(string, length, [set]) lpad('tech', 7); would return ' tech' lpad('tech', 2); would return 'te' lpad('tech', 8, '0'); would return '0000tech' lpad(‘this is my text', 15, 'z'); would return ' this is my text' lpad(' this is my text', 16, ‘#'); would return ‘#this is my text ' RPAD(string, length, [set]) rpad('tech', 7); would return 'tech ' rpad('tech', 2); would return 'te' rpad('tech', 8, '0'); would return 'tech0000' rpad(' this is my text', 15, 'z'); would return ' this is my text' rpad(' this is my text', 16, ‘$'); would return ' this is my text$'

String Function… LTRIM(string, [set]) ltrim(' tech'); would return 'tech' ltrim(' tech', ' '); would return 'tech' ltrim('000123', '0'); would return '123' ltrim('123123Tech', '123'); would return 'Tech' ltrim('123123Tech123', '123'); would return 'Tech1 ltrim('xyxzyyyTech', 'xyz'); would return 'Tech' RTRIM(string, [set]) rtrim('Tech123123', '123'); would return 'Tech' rtrim('123Tech123', '123'); would return '123Tech'

String Function… LOWER(string) lower('GEORGE BURNS 123 '); would return 'george burns 123 ' UPPER(string) upper('george burns 123 '); would return 'GEORGE BURNS 123 ' INITCAP(string) initcap('GEORGE BURNS'); would return 'George Burns' LENGTH(string) length(''); would return NULL. length(‘hello'); would return 5 length(‘ hello '); would return 7 SUBSTR(string, [count]) substr('This is a test', 6) would return 'is a test' substr('TechOnTheNet', 1, 4) would return 'Tech‘ substr('TechOnTheNet', -6, 3) would return 'The'

String Function… REPLACE( string1, string_to_replace, [ replacement_string ] ) replace('123123tech', '123'); would return 'tech' replace('123tech123', '123'); would return 'tech‘ -replace('222tech, '2', '3'); would return '333tech' replace('0000123', '0'); would return '123‘ CHR( number_code ) chr(116); would return 't' chr(84); would return 'T‘ ASCII( single_character ) ascii('t') would return 116 ascii('T') would return 84 ascii('T2') would also return 84

String Function… INSTR( string1, string2, [ start_position ], [ nth_appearance ] ) instr('this is my text', ‘s') ;would return 4 instr(‘this is my text', ‘s', 5, 1) would return 7 instr('this is my text', ‘s', 1, 2) would return 7 instr('this is my text', ‘s', -7, 2) would return 4

Date Functions SYSDATE SYSTIMESTAMP ADD_MONTHS CURRENT_DATE CURRENT_TIMESTAMP EXTRACT MONTHS_BETWEEN LAST_DAY NEXT_DAY

Date Functions… Sysdate Select emp_name, sysdate from employee; SYSTIMESTAMP SELECT SYSTIMESTAMP FROM dual; add_months( date1, n ) add_months('01-Aug-03', 3) would return '01-Nov-03' add_months('01-Aug-03', -3) would return '01-May-03‘ Current_Timestamp select systimestamp from dual; ALTER SESSION SET TIME_ZONE = '+5:30'; select current_timestamp from dual; select systimestamp from dual;

Date Functions… NEXT_DAY( date, weekday ) Where weekday: Monday, Tuesday… e.g. Select next_day(sysdate, ‘MONDAY’) from dual; LAST_DAY(date) select last_day(sysdate) LAST_DATE from dual; MONTHS_BETWEEN(date1, date2 ) select months_between(sysdate, to_date('1/1/2005', 'dd/mm/yyyy')) from dual;

GROUP BY The GROUP BY clause, along with the aggregate functions, groups a result set into multiple groups, and then produces a single row of summary information for each group. If we have a mix of aggregate and nonaggregate expressions in the SELECT list, SQL expects that we are trying to perform a GROUP BY operation, and we must also specify all nonaggregate expressions in the GROUP BY clause. When we GROUP BY a column that contains NULL values for some rows, all the rows with NULL values are placed into a single group and presented as one summary row in the output. While using GROUP BY Clause, we can filter records from the table based on a WHERE clause.

GROUP BY… e.g. select max(salary), min(salary), desig, avg(salary) from employee group by desig; Group By with NULL values; select count(*), department from employee group by department; With where Clause select max(salary), min(salary), desig, avg(salary), count(*) from employee where salary > 5000 group by desig;

GROUP BY HAVING The HAVING clause is used to put a filter on the groups created by the GROUP BY clause. If a query has a HAVING clause along with a GROUP BY clause, the result set will include only the groups that satisfy the condition specified in the HAVING clause. e.g. select desig, max(salary), avg(salary) from employee group by desig having avg(salary) > 5000;

ORDER BY The SQL ORDER BY clause comes in handy when you want to sort your SQL result sets by some column(s). SYNTAX: Select <field_name(s)> from <table_name(s)> ORDER BY <EXPR>, <FIELD(s) NAME> [ASC | DESC ] Specifies a column(s) on which to sort. The ORDER BY clause can include items not appearing in the select list, but in case of using keywords like DISTINCT then the sort columns must appear in the select list

Select Revisited Complete Syntax: SELECT select_list FROM table_source [ WHERE search_condition ] [ GROUP BY group_by_expression ] [ HAVING search_condition ] [ ORDER BY order_expression [ ASC | DESC ] ]

JOIN By using joins, you can retrieve data from two or more tables based on logical relationships between the tables. A join condition defines the way two tables are related in a query by: Specifying the column from each table to be used for the join. A typical join condition specifies a foreign key from one table and its associated key in the other table. Specifying a logical operator (=, <>, and so on) to be used in comparing values from the columns.

JOIN… Joins can be specified in either the FROM or WHERE clauses. The join conditions combine with the WHERE and HAVING search conditions to control the rows that are selected from the base tables referenced in the FROM clause. Syntax: FROM first_table join_type second_table [ON ( join_condition )]

JOIN… Joins can be categorized as: Inner joins (the typical join operation, which uses some comparison operator like = or <>). Inner joins use a comparison operator to match rows from two tables based on the values in common columns from each table. Cross joins return all rows from the left table, each row from the left table is combined with all rows from the right table. Cross joins are also called Cartesian products. Outer joins can be a left, a right, or full outer join.

OUTER JOIN Outer joins are specified with one of the following sets of keywords when they are specified in the FROM clause: LEFT JOIN or LEFT OUTER JOIN The result set of a left outer join includes all the rows from the left table specified in the LEFT OUTER clause, not just the ones in which the joined columns match. When a row in the left table has no matching rows in the right table, the associated result set row contains null values for all select list columns coming from the right table. RIGHT JOIN or RIGHT OUTER JOIN. A right outer join is the reverse of a left outer join. All rows from the right table are returned. Null values are returned for the left table any time a right table row has no matching row in the left table. FULL JOIN or FULL OUTER JOIN. A full outer join returns all rows in both the left and right tables. Any time a row has no match in the other table, the select list columns from the other table contain null values. When there is a match between the tables, the entire result set row contains data values from the base tables.

Scalar Subqueries The Scalar Subquery can be used anywhere a value can be used. When the subquery returns a single row, the value of the single select list column becomes the value of the Scalar Subquery. When the subquery returns no rows, a database null is used as the result of the subquery. Should the subquery retreive more than one row, it is a run-time error and aborts query execution.

Predicate Subqueries Predicate subqueries are used in the WHERE (and HAVING) clause. Each is a special logical construct. IN Subquery The IN Subquery tests whether a scalar value matches the single query column value in any subquery result row. General Syntax: value-1 [NOT] IN (query-1)

Predicate Subqueries… value-1 {=|>|<|>=|<=|<>} {ANY|ALL|SOME} (query-1) The comparison operator specifies how to compare value-1 to the single query column value from each subquery result row. The ANY, ALL, SOME specifiers give the type of match expected. ANY and SOME must match at least one row in the subquery. ALL must match all rows in the subquery

EXIST Subquery The EXISTS Subquery tests whether a subquery retrieves at least one row, that is, whether a qualifying row exists. General Syntax: EXISTS(query-1)

Table Subqueries Table Subqueries are queries used in the FROM clause, replacing a table name. Its the result set of the Table Subquery acts like a base table in the from list. Table Subqueries can have a correlation name in the from list.

Predicate Subqueries… EXIST Subquery The EXISTS Subquery tests whether a subquery retrieves at least one row, that is, whether a qualifying row exists. General Syntax: EXISTS(query-1)

NULLS "As we know, There are known knowns. There are things we know we know. We also know There are known unknowns. That is to say We know there are some things We do not know.”- Donald Rumsfeld What is NULL ????? NULL as "a special value , or mark , that is used to indicate the absence of any data value." NULL in SQL is not a "data value", but rather an indicator that we have missing data

NULLS… Nulls in Conditions: Condition Value of A Evaluation a IS NULL 10 FALSE a IS NOT NULL 10 TRUE a IS NULL NULL TRUE a IS NOT NULL NULL FALSE a = NULL 10 UNKNOWN a != NULL 10 UNKNOWN a = NULL NULL UNKNOWN a != NULL NULL UNKNOWN a = 10 NULL UNKNOWN a != 10 NULL UNKNOWN

NULLS… Nulls in SQL Functions All scalar functions (except REPLACE , NVL , and CONCAT ) return null when given a null argument. NVL( string1, replace_with ) e.g. select emp_name, nvl(department, 'N/A') from employee;

Alter Table ALTER TABLE table_name ADD ( column_1 column-definition, column_2 column-definition, ... column_n column_definition ); ALTER TABLE table_name MODIFY ( column_1 column_type, column_2 column_type, ... column_n column_type );

Alter Table… ALTER TABLE table_name DROP COLUMN column_name; ALTER TABLE table_name SET UNUSED column_name; ALTER TABLE table_name RENAME COLUMN old_name to new_name;

Alter Table… The Rules for Adding or Modifying a Column You may add a column at any time if NOT NULL isn’t specified. You may add a NOT NULL column in three steps: Add the column without NOT NULL specified. Fill every row in that column with data. Modify the column to be NOT NULL .

Alter Table… These are the rules for modifying a column: You can increase a character column’s width at any time. You can increase the number of digits in a NUMBER column at any time. You can increase or decrease the number of decimal places in a NUMBER column at any time. In addition, if a column is NULL for every row of the table, you can make any of these changes: You can change the column’s datatype. You can decrease a character column’s width. You can decrease the number of digits in a NUMBER column.

Alter Table… e.g. - Alter table mytable Add constraint pk_mytable PRIMARY KEY (a); - alter table mytable add b varchar2(50); Alter table emp_hourly MODIFY (HOURRATE NUMBER(5,2) DEFAULT 7.25); Alter table mytable RENAME CLOUMN a TO z; - Alter table mytable RENAME to mynewTable;

RENAME e.g. Rename mynewtable to mytable; RENAME old_table_name TO new_table_name;

DROP Table e.g. DROP table mytable; DROP TABLE table_name;

PL/SQL Lesson Objectives Introduction to PL/SQL SQL Review Basic PL/SQL Trigger Store Procedure and Function Package

Introduction What is PL/SQL: PL is stand for Procedural Language. PL/SQL= {Procedural or Structure Programming Language} + SQL PL/SQL is a procedural programming language which improving from SQL Language by added structured programming feature in order to process business logic of information system.

Feature of PL/SQL PL/SQL use to develop business logic layer of application which run on server-side. Feature of Server-Side Code are: - Good performance - Reduce network traffics - High security - High reusable

SQL There are 3 types of SQL Command: DDL: Data Definition Language . There are follow command of DDL - Create : for creating objects - Alter: for modifying objects - Drop: for removing objects DML (Data Manipulated Language): Use to manipulate data. DML Consist of - Select - Insert - Delete - Update DCL(Data Control Lanaguage) begin tran, commit,rollback,save tran

DML (Continue) Select Statement: for reading data from databases, the select statements return rows from tables: Syntax: Select *|Col1,Col2,….. From Table | Joined Tables [Where Condition] [Group By Col1,Col2,…] [Having Condition] [Order by Col1,Col2,…]

Transaction SQL Insert: for inserting records into tables: Syntax1: Insert Into Table_Name[(Col1,Col2,…)] Values(val1,val2,…) Syntax2 Insert Into Table_Name[(Col1,Col2,…)] Select co1l,col2,…from TableName…. Delete: for removing records (data) into tables: Delete from Table_Name [Where Condition] Update: for modifying records (data) in tables: Update Table_Name set Col1=Expr,Col2=Expr,… [Where Condition]

Basic PL/SQL Declare Variable: PL/SQL is a structure programming language. Before use a variable must be declare above the body of program. Syntax: Declare varname1 Datatype[:=initialvalue]; VarName Datatype[:=initialvalue]; Example Declare x integer; Str varchar2(20):=‘BBU’;

PL/SQL Data Type PL/SQL Data Type is similar to Oracle Database Data Type, However the size of some data type is difference Example varchar2 in database is 4K in pl/sql is 32k %TYPE is use to declare a variable to match with the other. Example Declare s varchar2(20); s1 s%type; pcode tblProducts.ProductCode%Type; %RowType is use to declare a variable to match a record type of a table or cursor. Example Declare prow tblProducts%RowType

Assignment and Operator Assignment is most important operator. In oracle we can assign to a variable an expression or value which on memory or we can select a value from a column or row of table then assign direct to variable. Syntax1: VarName:=Expression; Syntax2 Select Col1,Col2,…. INTO var1,var2 from tablename,. [Where Condition] Syntax 1 is assign a value or expression value to varname Syntax 2: is select a single row of data of col1,col2 from table then assign to var1,var2

Assignment (Cont) Example: Declare Code Varchar2(10); price float; Qty Integer; … … .. -- Assign ‘P001’ to Code Code:=‘P001’; -- Select Quatity and UnitPrice from tblProducts then assign to price and Qty. Select Quantity,UnitPrice Into Qty, Price from tblProducts Where ProductCode=‘P001’;

Control Structure IF Statement Syntax: If Condition then Statements; [elsif condition then statements; Elsif condition then statements; … ..] [Else statements; ] End if;

Loop Statement Syntax Loop Statement1; Statement2; Exit When Condition; … . End Loop; Loop execute by repeating statement1,statement2,.... To exit loop use following: Exit When Condition or if Condition Then Exit

While Loop Syntax While Condition Loop Statement1; Statement2; ……………… . End loop;

For Statement In oracle for statement can be used to loop and scan value in collection of value or collection of records the counter variable will automatic define it data type to match collection. Syntax For counter IN Collection Loop Statements; Statements; Statements; End Loop;

For Statement Example: for I in 1..100 loop Statements; end loop; -- statement I run from 1 to 100 For pRow IN (Select * from tblProducts) Loop Statements; END LOOP; In above statement pRow is a record variable which will be stored each record.

Case Statement In oracle case statement, use to return value like a value. Syntax1: Case When Condition Then Value1 When Condion Then Value2 … .. [else valN] END Syntax 2 Case Expression When val1 Then Value1 When val2 Then Value2 [else valN] END;

CURSOR Cursor is a data type which its variable use to store address of records returned from select statement. Declare Cursor Cursor_Name[(Parameter,…)] is select statement; To use cursor first open cursor then read data from cursor parse to variable Syntax Open Open Cursor_name[(arg,…)] Syntax Read Fetch Cursor_Name into var_name; Var_name must be declare as Cursor_name%rowtype. The fetch statement always move next rows while eof the Attribute cursor_name%notfound=true Close Cursor Close Cursor_Name

Trigger Trigger is a special procedure or sub program is bound to a table’s transaction and will be execute when the bound table receive transaction. There two type of Trigger: Row Trigger and Statement Trigger Row trigger is trigger which will execute every row effect by transaction. Statement trigger is execute a time for every statement. It’s does not depend on how many rows created by transaction

Trigger Syntax: Create [or replace] trigger trigger_name After|Before Transaction On Table_name [For Each row ] [When condition] --Declare parts Begin --PL/SQL Codes; End; Transaction : [INSERT [Or Delete Or [Update [of ColumnName,…]]]

Trigger :New and :Old :New is a trigger parameter store the inserted records and new records of update statement. :Old is a trigger parameter store the deleted records and previous records of update statement. INSERTING,DELETING,UPDATING is a Boolean parameter use to recognize transaction type.

Procedure and Function Create [Or Replace] Procedure Name-Of-Procedure(Par,…..) IS --Variable declaration Begin --PL/SQL Statement; End; Create Or Replace Function Name-Of-Function (Par,…..) Return DataType IS --Variable declaration Begin --PL/SQL Statement; Return Value,-- return the value to function End;

Procedure and Function Parameters are variable use for receiving value from argument and parsed value to arguments. Syntax: Par-Name [IN|OUT|IN OUT] DataType IN parameters use to receive value only from clients; OUT Parameter use to parse value from server to client’s arguments. IN OUT parameter for both receive and parsed. Parameter cannot specific size

Learning Topics: Create Users Privileges and Granting Privileges Role Auditing Users

Create Users A user is a key to access database. An user must be provided some privileges (right) for access database objects and perform tasks. Syntax Create User Create User UserNam e Identified by password [Password expire] [Default Tablespace name-of-tablespace ] [Temporary tablespace name-of-temporary-tablespace ] [Quota {Size|Unlimited} on Tablespace-Name ] ---------;

Create Users(Continue) - User-Name must be string and no duplicate Password is user password Password Expire an option for user change password at first time log on Default tablespace is tablespace to store object will be created by users. Temporary tablespace is name of temporary tablespace will store data query of users. Quota is the permission to use tablespace

Create User (Example) Ex1 Create User BBUMSC Identified by bbu Password Expire Default tablespace users Temporary tablespace temp Quota 100M on Users; Ex2: Create User BBUCEO Identified by bbumanager Temporary tablespace temp;

Privileges Privilege is right to access oracle system: There are two type of Privileges System Privilege And Object Privileges System Privileges: Right to access system resources. System Privileges consist of: Create Session Select ANY TABLE INSERT ANY TABLE UPDATE ANY TABLE DELETE ANY TABLE CREATE TABLE,CREATE VIEW,CREATE TABLESPACE,….

Privileges (Continue) Granting System Privileges: Grant Privileges,… to USERNAME [With Grant Option] Example Grant Create Session,Select Any Table,Create Tablespace,Create Table to BBUMSC;

Privileges (Continue) Are right to access data in table, view and execute store procedure, function and package: Object Privileges consist of: Select Insert Delete Update Execute Syntax: Granting Object Privileges: Grant All|Select,Insert On ObjectName to UserName [With Grant Option]; Example: Grant All on Students to BBUMSC;

Roles Role is a set of privileges use to grant to users. Syntax Create Role: Create Role RoleName; To grant privileges to role is the same user. Example: Create Role StudentRole; Grant create session,Select any table to StudentRole; Grant StudentRole to BBUMSC;

Auditing User Use to control action of users who access to oracle system. Syntax: Audit option,.. [by user] [by access|by session] [whenever [not] successful]; Audit Option - Select Table - Delete Table - Update Table - Insert Table - Session - ……..

Auditing User (Continue) To set audit user: - Set Parameter file AUDIT_TRAIL=True - User Audit Command - Check Audit on view

Oracle Backup & Recovery Chapter 8

Oracle Backup & Recovery 4-1 Backup/Recovery Basic 4-2 Oracle Backup/Recovery Configuration 4-3 Physical Backups 4-4 Types of Failure and Troubleshooting 4-5 Oracle Recovery without Archiving 4-6 Complete Recovery with Archiving 4-7 Incomplete Recovery with Archiving 4-8 Recovery when loss of Control Files / Online Redo Logfiles

Oracle backup/recovery basic Backup methods Backup strategy

Backup methods Logical backup export/import Database, user, table, table partition full increasement Physical backup cold/offline backup full increasement hot/online backup full Increasement archive log backup

Backup strategy Determinded by Business Technical Management Mean-time to recover

Determine backup strategy Ask customer: What’s your backup strategy now? How many data can you loss? How long can your database be shutdonw? How long can you allow to backup? How long can you allow to recover? How many archived logs per day? How many free disk space do you have to store the archived logs? Do you consider about standby database?

Objectives Identify recovery implications of operating in “Noarchive” mode Describe the differences between “Archivelog” mode and “Noarchivelog” mode Configure a database for “Archivelog” mode and automatic archiving Use init.ora parameters to duplex archive log files

Overview Noarchivelog or Archivelog Mode Decision to use one or the other is dependent upon how much data can be lost due to a failure.

Online redo log files 053 No redo history NOARCHIVELOG Mode 054 054 053 053 LGWR

Archivelog Mode Online redo log files LGWR Archived log files 054 054 053 053 053 052 051 Redo history

Configuring for Archiving ARCH LOG_ARCHIVE_DEST=/archive/arch LOG_ARCHIVE_FORMAT=%s.arc /archive/arch052.arc Archived log file Online redo log files 053 053 052 Group 1 Group 2 052 052

Duplexing Archived Log Files ARCH Online redo log files 053 053 052 052 LOG_ARCHIVE_DUPLEX_DEST 052 052 Group 1 Group 2 LOG_ARCHIVE_DEST Archived log files

Changing Database Archive Modes Startup and mount the database Alter the mode of the database Shutdown in normal or immediate Take a full closed database backup Startup and open the database

Enabling Archive Processing Automatic archiving Manual archiving ARCH 053 053 053 053 DBA

Manual Archive ALTER SYSTEM ARCHIVE LOG all; 1 2 ARCH 052 051 052 3 051 Online redo logs

Automatic Archiving ARCH 052 051 Archived log files 053 051 052 Archived Archived Current LOG_ARCHIVE_START=TRUE Online redo logs

Obtaining Archive Log Information V$ARCHIVE_DEST V$ARCHIVED_LOG V$LOG_HISTORY Data dictionary views Command line ARCHIVE LOG LIST; V$DATABASE

Summary Complete database recovery requires: Archivelog mode Automatic archiving A database backup immediately after it is put into archivelog mode

Exercise 4-2 1. See database is running on archive or noarchive log mode: svrmgr>select * from v$database; 2. Set database to archive log mode: Edit init_sid.ora files archive_log_dest archive_log_format (see Oracle References about values) log_archive_start svrmgr> shutdown immediate; svrmgr> startup mount; svrmgr> alter database archivelog; svrmgr> alter database open;

Exercise 4-2 3. Check archive log configuration: Check the archive process: $ps –ef|grep arch Check archive log parameters: svrmgr> show parameter arch

Objectives Perform database backups using operating system commands Describe the recovery implications of closed and open database backups Perform closed(offline) and open(online) database backups Identify the different types of control file backups List the data dictionary views useful for backup operations

Backup Methods Physical backup Closed database Open database Archive Mode No archive Mode

Closed Database Backup Datafiles Control Files Password File Online or Offline Storage Parameter Files Redo Log Files

Advantages of Closed Database Backups Conceptually simple Easy to perform Requires little operator interaction Reliable

Database File Information Data dictionary views V$DATAFILE V$CONTROLFILE V$LOGFILE DBA_DATA_FILES

Performing a Closed Database Backup 2 3 4 SHUTDOWN IMMEDIATE; HOST cp <files> /backup/ STARTUP OPEN; Data Files Control Files Parameter Files 1

Open Database Backup Datafiles Control Files Parameter Files Archived Redo Log Files Password File Online Redo Log Files

Advantages of Open Database Backups Maintains high database availability Can be done at a tablespace or datafile level Allows recovery to point-in-time

Archived Log Files ARCH Archivelog Mode Online Redo Log Files LGWR 054 054 053 053 052 051 Open Database Backup Requirements 053

Open Database Backup Options All tablespace datafiles Tablespace USER_DATA user02.dbf user01.dbf Individual datafile user02.dbf Tablespace USER_DATA user01.dbf

Performing an Open Database Backup 1 ALTER TABLESPACE user_data BEGIN BACKUP; 2 HOST cp <files> /backup/ 3 ALTER TABLESPACE user_data END BACKUP;

Backup Status Information Data dictionary views: V$BACKUP V$DATAFILE_HEADER

Backing Up a Control File Creating a binary image: alter database backup controlfile to ‘control1.bkp’; Creating a text trace file: alter database backup controlfile to trace;

Exercise 4-3 1. Cold backup: Shutdown database Copy datafile, control file, logfile, init file, password file to other place 2. Hot backup: svrmgr>ALTER TABLESPACE system BEGIN BACKUP; svrmgr>host cp /abc/system01.dbf /backup svrmgr>ALTER TABLESPACE system END BACKUP;

Categories of Failures Statement failure User process failure User error Instance failure Media failure

Causes of Statement Failures Logic error in an application Attempt to enter bad data into the table Attempt an operation with insufficient privileges Attempt to create a table but exceed allotted quota limits Attempt an INSERT or UPDATE to a table, causing an extent to be allocated, but with insufficient free space left in the tablespace

Resolutions for Statement Failures Correct logic flow of the program Modify and reissue the SQL statement Provide the necessary database privileges Change the user’s quota limit by using the ALTER USER command Add file space to the tablespace

Causes of User Process Failures The user performed an abnormal disconnect in the session The user’s session was abnormally terminated The user’s program raised an address exception terminating the session

Resolving User Process Failures The PMON process detects an abnormally terminated server process PMON rolls back the transaction and releases any resources and locks being held by it

Possible User Error Failures SQL> DROP TABLE Employee; SQL> TRUNCATE TABLE Employee; SQL> UPDATE Employee SET SALARY = SALARY * 1.5; SQL> COMMIT; SQL> DELETE FROM Employee;

Resolving User Errors Train the database users Recover from a valid backup Bring back a table export Perform a point-in-time recovery

Causes of Instance Failure Power outage Hardware failures CPU Memory Disk failure Background process failure

Recovery from Instance Failure No special recovery action required Start the instance Open the database Notify users

Instance Recovery Process Unsynchronized files Roll-forward process Committed and uncommitted data in files Rollback process Committed data in data files Synchronized files

Causes of Media Failure Head crash on disk drive Physical problem reading or writing to database files File was accidentally erased

Resolving Media Failures The recovery strategy depends upon which backup method was chosen and which files are affected If available, apply archived redo log files to recover data committed since the last backup

Database Synchronization All data files (except offline and read-only) must be synchronized for the database to open Synchronization is based on the current checkpoint number Applying redo logs synchronizes files Redo logs are automatically requested by Oracle

The Alert Log File Records informational and error messages for Oracle Reflects the ongoing status of the system Continuously written to, with new messages being appended to the end of the alert file Shows date and time of startup, shutdown, recovery operations, and so on

Oracle Trace Files Created by Oracle background processes Written to destination specified by parameter BACKGROUND_DUMP_DEST Source of additional diagnostic information

Summary Understand the types of failures and the degree of DBA intervention Locate error messages in the alert log and trace files

Exercise 4-4 View alert log to calculate archive log size per day

Objectives Note the implications of media failure with a database in noarchivelog mode Recover a database in noarchivelog mode after media failure Restore files to a different location if media failure occurs

Overview Database Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 146 145 146 146 146 146 Instance SGA Redo Log Buffer Data Buffer Large Pool Locks Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA User Process Server Process PGA Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 144 145 144 144 144 144

Media Failure and Recovery Without Archiving Failure Loss of disk, datafile, or corruption Recovery Restore all datafiles, control files, and redo logs Restoring password and parameter files is optional

Recovery Without Archiving Advantages Easy to perform, with low risk of error Recovery time = Time to restore all files Disadvantages Data is lost and must be reapplied manually The entire database is restored to the point of the last whole closed backup

Recovery Without Archiving Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database 145 146 146 146 146 146 Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Backup 143 144 144 144 144 144 Restore most recent backup Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database 143 144 144 144 144 144

Restoring to a Different Location Rename the file or directory location: SVRMGR> connect system/manager as sysdba; Connected. SVRMGR> startup mount pfile=initDB00.ora; Oracle instance started. SVRMGR> alter database rename file 2> ‘/disk1/data/user_01.dbf’ 3> to ‘disk2/data/user_01.dbf’; Statement Processed. SVRMGR> alter database open;

Overview Database Database Password File Archived Log Files Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 146 145 146 146 146 146 User Process Server Process PGA Data File 2 146 Instance SGA Redo Log Buffer Large Pool Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH Data Buffer Cache

Media Failure and Recovery with Archiving Failure Loss of disk, datafile, or corruption Recovery Datafiles for restore must be offline Restore only lost or damaged datafiles Do not restore the control file, redo logs, password, or parameter files Recover the datafiles

Recovery with Archiving (Complete Recovery) Advantages Only need to restore lost files Recovers all data to the time of failure Recovery time = Time to restore lost files and apply all archived logs Disadvantages Must have all archived logs since the backup from which you are restoring

Complete Recovery Methods 1. Closed database recovery: For system, rollback segment data files, or whole database 2. Open database recovery, with database initially open: For file loss 3. Open database recovery with database initially closed: For hardware failure 4. Recover a datafile with no backup

Complete Recovery: Method 1 145 146 Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database 146 145 146 146 146 146 Archived Log File 144 Restore Data File 2 (Log Seq 144) Data File 2 144 1 Instance SGA Redo Log Buffer Data Buffer Large Pool Locks Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA Instance SGA Redo Log Buffer Large Pool Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA Mount Instance 2 Data Buffer Cache Apply Log Files 3 Open the database 4

Complete Recovery: Method 2 Instance SGA Redo Log Buffer Large Pool Shared Pool Data Dict. Cache Shared SQL & PLSQL ARCH 145 146 Data Buffer Cache Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database 146 145 146 146 146 146 Archived Log File 144 Offline Data File 2 Data File 2 146 1 PMON DBWR SMON LGWR CKPT User Process Server Process PGA Restore Data File 2 (Log Seq 144) Data File 2 144 2 Apply Log Files 3 Online Data File 2 Data File 2 146 4

Complete Recovery: Method 3 145 146 Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database 146 145 146 146 146 146 Archived Log File 144 Mount the database 1 Instance SGA Redo Log Buffer Data Buffer Large Pool Locks Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH Instance SGA Redo Log Buffer Large Pool Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA Data Buffer Cache Offline Data File 2 Data File 2 146 2 Open Database 3 Restore Data File 2 (Log Seq 144) Data File 2 144 4 Apply Log Files 5 Online Data File 2 Data File 2 146 6

Complete Recovery: Method 4 145 146 Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database 146 145 146 146 146 146 Archived Log File 144 Offline Data File 2 Data File 2 146 1 Recreate Data File 2 (Log Seq 144) Data File 2 144 2 Apply Log Files 3 Online Data File 2 Data File 2 146 4 Instance SGA Redo Log Buffer Large Pool Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA Data Buffer Cache

Recover Syntax Recover a closed database: SVRMGR> recover database; SVRMGR> recover datafile > ‘/disk1/data/df2.dbf’; SVRMGR> alter database recover; SVRMGR> recover tablespace USER_DATA; SVRMGR> recover datafile 2; SVRMGR> alter database recover datafile 2; Recover an open database:

Recovery Using Archived Logs To change archive location, use the ‘alter system archive log …’ command To automatically apply redo log files: Issue ‘set autorecovery on’ before starting media recovery Enter ‘auto’ when prompted for an archived log file Use the ‘recover automatic’ command

Files Needed for Recovery View V$RECOVER_FILE to locate datafiles needing recovery View V$ARCHIVED_LOG for a list of all archived logs for the database View V$RECOVERY_LOG for a list of all archived logs required for recovery

Overview Database Password File Archived Log Files Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 146 145 146 146 146 146 Instance SGA Redo Log Buffer Data Buffer Large Pool Locks Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA User Process Server Process PGA

Reasons for Incomplete Recovery User error Complete recovery fails because an archived log is lost Recovery using a backup control file Loss of all unarchived redo logs and the datafile

Recovery with Archiving (Incomplete Recovery) Advantages Recovers prior to the time of failure Provides recovery in situations where complete recovery is not possible Disadvantages Database taken back in time (lose data) Recovery time = Time to restore all datafiles + apply required archived logs

Types of Incomplete Recovery Time-based recovery Cancel-based recovery Recovery using a backup control file Change-based recovery

“ recover” Command Syntax Recover a database until cancel: SVRMGR> recover database until cancel; SVRMGR> recover database 2> until time ‘1997-12-04:14:22:03’; Recover a database until time: SVRMGR> recover database 2> until time ‘1997-12-04:14:22:03’ 3> using backup controlfile; Recover using backup control file:

Recovery Steps 1. Shut down and backup the database 2. Restore all data files 3. Do not restore the control file, redo logs, password, or parameter files 4. Mount the database and recover the datafiles before the time of failure 5. Open the database with “resetlogs” 6. Perform a closed database backup

Recovery Guidelines Follow/Record all steps since most errors occur during this type of recovery Take whole database backup before and after recovery to assist future recovery Always check if recovery is successful Backup the control file regularly Backup archived logs

Time-Based Recovery Scenario: The current time is 12 PM on 9-DEC-97 Your training DBA just told you he dropped the employee (EMP) table The table was dropped around 11:45 AM Database activity is minimal because most staff are currently in a meeting The table must be recovered

“ Until Time” Recovery Instance SGA Redo Log Buffer Data Buffer Large Pool Locks Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH User Process Server Process PGA User Process Server Process PGA Shutdown and backup the database 1 Mount database 2 Instance SGA Redo Log Buffer Data Buffer Large Pool Locks Shared Pool Data Dict. Cache Shared SQL & PLSQL PMON DBWR SMON LGWR CKPT ARCH Password File Parameter File Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 Database EMP 146 145 146 146 146 146 Archived Log File 144 Restore all Data Files (Log Seq 144) 3 Data File 3 Data File 2 Data File 1 144 144 144 EMP 4 5 145 145 145 146 145 145 145 145 146 Data File 3 Redo log File 2 Data File 2 Control Files Redo log File 1 Data File 1 1 0 1 1 1 1 EMP Open Database 揜 esetlogs 6 User Process Server Process PGA User Process Server Process PGA Backup database 7

Cancel-Based Recovery Scenario: The current time is 12 PM on 9-DEC-97 Your training DBA dropped the EMP table while trying to fix bad blocks Log files exist on the disk containing the employee data file The table was dropped around 11:45 AM

Cancel-Based Recovery Findings: Redo logs are not multiplexed One of the online redo logs is missing The missing redo log is not archived The redo log contained information from 11:34 AM Twenty six minutes of data will be lost Users can recover their data

Backup Control File Recovery Scenario: The current time is 12 PM on 9-DEC-97 Your training DBA dropped the entire employee tablespace, not just the table The error occurred around 11:45 AM Many employee records were updated this morning, but not since 11:00 AM Backups are taken every night

Backup Control File Recovery Findings: The backup last night contains datafiles and control files required for recovery Employee tablespace has one datafile The current log sequence number is 61 You confirm that the tablespace was dropped at 11:44:54 AM on 9-DEC-97. Datafile number 4 is offline.

Recover database syntax RECOVER [AUTOMATIC] DATABASE [USING BACKUP CONTROLFILE] [UNTIL < CANCEL | TIME date | CHANGE integer> ] [NOPARALLEL | PARALLEL [integer] ]

Loss of control files Should not loss of all control files if configured multiple control files If loss all control files: Method 1: Recreate control file Method 2: Restore backup control file

Recreate control files You must get all database structure before recreate control files

Recreate control file svrmgr>alter database backup controlfile to trace; The create control file command will exist in the latest trace file Edit the trace file and save to script Run the create control file script

Restore backup control file Restore backup control file svrmgr> recover database using backup controlfile;

Loss of a Redo Log File Loss of a Redo Log file: Archiving still occurs using a good online redo log file Loss of all redo log files for a group should ‘NEVER’ occur if the database is configured properly using mirrored redo log files

Redo Log File Recovery Non-Current logs: Add group, drop group Current logs: If database shutdown normally: 1. Recover database until cancel 2. Alter database open resetlogs If database shutdown abnormally: Have backups: Restore from backups RECOVER DATABASE UNTIL CANCEL and cancel when prev log applied No backup Can be startup in a corruption status Ask Oracle support

Scenario 1 Loss of non-current logfiles: svrmgr>alter database add logfile ‘new_file_name’ size 1m; svrmgr>alter database drop logfile <‘old_file_name’ | group n>

Scenario 2 Loss of current logfile and instance is shutdown normally: svrmgr>recover database until cancel; cancel svrmgr>alter database open resetlogs;

Scenario 3 Loss of current logfile and instance is shutdown abnormally: Have backups Restore backups svrmgr>recover database until cancel; svrmgr>alter database open resetlogs; No backups Ask Oracle support _allow_resetlogs_corruption in init_sid.ora svrmgr>recover database using backup controfile until cancel; svrmgr>alter database open resetlogs; Export database

ora_sothea

Recommended

More Related Content

What's hot (13)

Viewers also liked (7)

Similar to ora_sothea (20)

Recently uploaded (20)

ora_sothea

Editor's Notes