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Oracle DBA Topics

Overview of Oracle Grid Architecture

Difference between cluster and grid

Responsibilities of DBA's

Creating Oracle Database

Creating Database using SQL

Creating DB in 12c using DBCA

Creating DB in 12c using SQL commands

Managing Oracle 12c Container Databases

Creating Users in Oracle 12c

Managing Pluggable Databases in Oracle 12c

Creating Pluggable Database

Cloning Pluggable Database

Unplug and Plug databases in CDB's

Managing Tablespaces and Datafiles

Extending tablespaces

Decreasing size of a tablespace

Coalescing Tablespaces

Taking tablespaces Offline or Online

Making a Tablespace Read only

Renaming Tablespaces

Dropping Tablespaces

Viewing Info about Tablespaces

Renaming Datafiles

Relocating Datafiles

Relocating Datafiles in Multiple Tablespaces

Temporary Tablespace

Changing the size

Tablespace Groups

Creating a Temp. Tablespace Group

Assigning a Tablespace Group

Diagnosing and Repairing LMT

Scenario 1: Fixing Bitmap

Scenario 2: Dropping a Corrupted Segment

Scenario 3: Fixing Bitmap when Overlapped

Scenario 4: Correcting Corruption of Blocks

Scenario 5: Migrating from a Dictionary-Managed to LMT

Transporting Tablespaces

Procedure for transporting tablespaces

Transporting Tablespace Example


Adding New Redo Logfile Group

Adding Members to group

Dropping Members from group

Dropping Logfile Group

Resizing Logfiles

Renaming or Relocating Logfiles


Viewing Info About Logfiles

Managing Control Files

Multiplexing Control File

Changing the Name of a Database

Creating A New Control File

Cloning an Oracle Database


Switching to Automatic Management

Calculate Undo Retention

Altering UNDO Tablespace

Dropping an Undo Tablespace

Switching Undo Tablespaces

Viewing Information

SQL Loader


From Fixed Length file

From MySQL to Oracle

Using WHEN condition

Conventional and Direct Path Load

Direct Path

Restrictions on Using Direct Path Loads

Export and Import

Invoking Export and Import

Parameters of Export tool

Exporting Full Database

Exporting Schemas

Exporting Tables

Exporting Consistent Image of tables

Using Import Utility

Example Importing Tables

Import from One User to another User

Using Pattern Matching

Migrating a Database across platforms


Data Pump Export

Exporting a Full Database

Exporting a Schema

Exporting Individual Tables

Filtering Objects during Export

Filter Rows during Export

Suspending and Resuming Export

Data Pump Import Utility

Importing Full Dump File

Importing Objects between Schemas

Loading Objects between Tablespaces

Generating SQL File of DDL commands

Import objects of a Schema

Importing Only Particular Tables

Interactive Mode

Flash Back Features

Flashback Query

Flashback Version Query

Flashback Table to Past States

Purging Objects from Recycle Bin

Flashback Objects With Same Name

Flashback instead of PIT Recovery

Enabling Flash Back Database

Sizing flash recovery area

How far we can flashback database

Example:Flashing Back Database

Flashback Data Archive (FDA)
(Oracle Total Recall)


Creating FDA tablespace

Creating FDA

Querying historical data

Log Miner

LogMiner Configuration

LogMiner Dictionary Options

Using the Online Catalog

Extracting Dictionary to Log Files

Extracting Dictionary to File

Redo Log File Options

Example: Finding All Modifications

Mining Logfiles in a Time Range


Opening DB in Archivelog Mode

Reverting back to NoArchiveLog mode

Taking Offline (COLD) Backups

Taking Online (HOT) Backups

Recovering from the Loss of a Datafile

When in Noarchivelog Mode

When in Archivelog Mode

Recovering from loss of Control File

Recovery Manager ( RMAN )

Offline Backups using RMAN

Recover DB when in NOARCHIVELOG

Online Backups using RMAN

Backup tablespaces or datafiles

Image Backups in RMAN

Incremental Backup using RMAN

Updating backup copy for fast recovery

View info about RMAN backups

Configuring Retention policy

Configure Options in RMAN

Maintaining RMAN Repository

Recover datafiles (Archivelog mode)

Recover datafiles by renaming

Performing Disaster Recovery










Managing Control Files in Oracle database

Every Oracle Database has a control file, which is a small binary file that records the physical structure of the database. The control file includes:

It is strongly recommended that you multiplex control files  i.e. Have at least two control files one in one hard disk and another one located in another disk, in a database.  In this way if control file becomes corrupt in one disk the another copy will be available and you don’t have to do recovery of control file.

You can  multiplex control file at the time of creating a database and later on also. If you have not multiplexed control file at the time of creating a database you can do it now by following given procedure.

Multiplexing Control File


 1.  Shutdown the Database.


 2. Copy the control file from old location to new location using operating system command. For example.

$ cp /u01/oracle/ica/control.ora  /u02/oracle/ica/control.ora

 3. Now open the parameter file and specify the new location like this


Change it to


 4. Start the Database

Now Oracle will start updating both the control files and, if one control file is lost you can copy  it from another location.

Changing the Name of a Database

If you ever want to change the name of database or want to change the setting of MAXDATAFILES, MAXLOGFILES, MAXLOGMEMBERS then you have to create a new control file.

Creating A New Control File

Follow the given steps to create a new controlfile


1.  First generate the create controlfile statement

SQL>alter database backup controlfile to trace;

After giving this statement oracle will write the CREATE CONTROLFILE statement in a trace file. The trace file will be randomly named something like ORA23212.TRC and it is created in USER_DUMP_DEST directory.

2.  Go to the USER_DUMP_DEST directory and open the latest trace file in text editor. This file will contain the CREATE CONTROLFILE statement. It will have two sets of statement one with RESETLOGS and another without RESETLOGS. Since we are changing the name of the Database we have to use RESETLOGS option of CREATE CONTROLFILE statement. Now copy and paste the statement in a file. Let it be c.sql

3.  Now open the c.sql file in text editor and set the database name from ica to prod shown in an example below

   SET DATABASE prod   
   LOGFILE GROUP 1 ('/u01/oracle/ica/redo01_01.log',
           GROUP 2 ('/u01/oracle/ica/redo02_01.log',
           GROUP 3 ('/u01/oracle/ica/redo03_01.log',
   DATAFILE '/u01/oracle/ica/system01.dbf' SIZE 3M,
            '/u01/oracle/ica/rbs01.dbs' SIZE 5M,
            '/u01/oracle/ica/users01.dbs' SIZE 5M,
            '/u01/oracle/ica/temp01.dbs' SIZE 5M

4. Start and do not mount the database.


5. Now execute c.sql script

SQL> @/u01/oracle/c.sql

6.  Now open the database with RESETLOGS




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