Hi Vinod,

Here are your answer's ...

There are two main administrative privileges in Oracle: SYSOPER and SYSDBA
These are special privileges as they allow access to a database instance even when it is not running and so control of these privileges is totally outside of the database itself.

SYSOPER privilege allows operations such as:
Instance startup, mount & database open ;
Instance shutdown, dismount & database close ;
Alter database BACKUP, ARCHIVE LOG, and RECOVER.
This privilege allows the user to perform basic operational tasks without the ability to look at user data.

SYSDBA privilege includes all SYSOPER privileges plus full system privileges (with the ADMIN option), plus 'CREATE DATABASE' etc.. This is effectively the same set of privileges available when previously connected INTERNAL.

Internal get connected to instance through ORACLE.EXE and
since the control of this privileges is totally outside the database, it doesn't matter whether database is up or down.



Regards,
Vicky