RMAN Backup and Recovery Scenario Point-In-Time Recovery

Backup and Restore Scenario from existing Level 0 backup
-------------------------------------------------------
steps to recover the database:-

1. Take Level 0 backup.
2. Lost SYSTEM datafile.
3. Start the instance without mounting the database.
4. Restore Controlfile.
5. Mount the database.
6. Restore database.
7. Recovery database.
8. Open the database and reset logs.

1. Take Level 0 backup:

run
{
allocate channel channel1 type disk;
allocate channel channel2 type disk;
allocate channel channel3 type disk;
backup incremental level=0 database;
backup archivelog all;
backup current controlfile;
}

2. Lost SYSTEM datafile.

Note:
----
Need controlfile, backup and parameter file for recoverying database.

3. Start the instance without mounting the database.

$sqlplus "/as sysdba"

SQL> startup nomount;
SQL> exit

4. Restore Controlfile.

$rman target /
RMAN> restore controlfile;

5. Mount the database.
RMAN> alter database mount;

6. Restore and recover & Point-In-Time Recovery of all data back to a particular date/time in the past.
run
{
set until time "to_date('2013-03-20:14:40:00','YYYY-MM-DD:hh24:mi:ss')";
restore database;
recovery database;
}

7.Open the database and reset logs.

SQL> alter database open resetlogs;
This will update all current datafiles and online redo logs and all subsequent archived redo logs with a new RESETLOGS SCN and time stamp.

NOTE:
----
As soon as you have done a resetlogs run a full backup, this is important as should you suffer a second failure you will not be able to perform a second recovery because after resetting the logs the SCN numbers will no longer match any older backup files.

http://ss64.com/ora/rman_pitr_example.html