In oracle as we are aware there are system tables which give us the information. Oracle internally converts a lot of things captialized, so dba_users is the table to view. How do you check with the query
1. select username from dba_users where username = '
If this shows an entry that means the user exists in the database.
Some more interesting views for user management are :
i) dba_ts_quotas ( for viewing tablespace quotas )
( Will update this more as I find out about them)
Ok so today i get some time to update this site some more tables that might interest DBA in Oracle 9i are