ORA-01157/ORA-01110: cannot identify/lock data file 12 – see DBWR trace file As you can see while starting of the database, the datafile 12 is missing/corrupted and through the ora error as shown: sys@TESTDB> startup ORACLE instance started. Total System Global Area 2455228416 bytes Fixed Size                 … Read more..

Offline (Cold) backup of database in Oracle 11gRr2 Fallow the step by step procedure as shown below: Shutdown the database sys@TESTDB>shu immediate Database closed. Database dismounted. ORACLE instance shut down. Now manually copy all the datafiles, logfiles, controlfiles, parameter… Read more..

Online (Hot) backup of datafile To perform the online backup of the database, the database should be running in archivelog mode, below query: Check the database Instance Name & Version sys@TESTDB>select INSTANCE_NAME, VERSION from v$instance; INSTANCE_NAME    VERSION ———————————————— testdb          … Read more..

Disable database in NOARCHIVELOG mode in Oracle database 11gR2 Check the database Instance Name & Version sys@TESTDB>select INSTANCE_NAME, VERSION from v$instance; INSTANCE_NAME    VERSION —————- ———- testdb           11.2.0.4.0 Check the status of the… Read more..

Enable database in Archivelog mode in Oracle database 11gR2 Check the database Instance  Name & Version sys@TESTDB>select INSTANCE_NAME, VERSION from v$instance; INSTANCE_NAME    VERSION —————- —————– testdb           11.2.0.4.0 Check… Read more..

Managing the UNDO TABLESPACE in Oracle database 11gR2 In an Oracle DB the undo tbs is used for maintaining the information that is used to rollback or any undo changes to the database. The Undo records are more used as shown below: Rollback the transactions when a ROLLBACK statement is issued Recover… Read more..