We can open standby database in read-write mode .When switched back into standby mode, all changes made whilst in read-write mode are lost is know as Snapshot standby database .
Priversly This is achieved using flashback database, but from 11g standby database does not need to have flashback database explicitly enabled to take advantage
of this feature, thought it works just the same if it is.
How To Set Up Physical Standby Database You Can Check Here
http://adminoracle10g.blogspot.in/2014/08/physical-standby-database-implementation.html
Steps
1) Bring database in mount stateSHUTDOWN IMMEDIATE;
STARTUP MOUNT;
2) Disable recovery on standby
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
3) Convert standby database to flashback
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
4) Open database
ALTER DATABASE OPEN;
5) Check database status
Select NAME, OPEN_MODE, DATABASE_ROLE from v$database;
NAME OPEN_MODE DATABASE_ROLE
————– ———- —————-
ORCL_STBY READ WRITE SNAPSHOT STANDBY
SELECT flashback_on FROM v$database;
FLASHBACK_ON
RESTORE POINT ONLY
6) To convert it back to the physical standby, losing all the changes made since the conversion to snapshot standby, issue the following commands.
SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ALTER DATABASE CONVERT TO PHYSICAL STANDBY;
SHUTDOWN IMMEDIATE;
STARTUP NOMOUNT;
ALTER DATABASE MOUNT STANDBY DATABASE;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;
SELECT flashback_on FROM v$database;
Select NAME, OPEN_MODE, DATABASE_ROLE from v$database;
NAME OPEN_MODE DATABASE_ROLE
————– ———- —————-
ORCL_STBY READ WRITE PYSICAL STANDBY
FLASHBACK_ON
NO
