How to deal with Oracle forgetting user name and password

1. Ensure that the system users you log on to have sufficient permissions.

Windows: add your users to the Oracle DBA Group. Use root to log on to UNIX.

2. Run sqlplus/nolog in command

3. Enter the conn/as sysdba after the SQL> command

If the following error occurs.

ERROR:

ORA-12560: TNS: protocol adapter error

This may be because you have multiple database instances. Enter the following before Step 2:

Set oracle_sid = XXXX, XXXX is your database SID.

4. Enter alter user system identified by *** after the SQL> command ****;

The asterisk is your password.