How to Unlock the Account in Oracle (with Pictures) - wikiHow

A user account can be locked by an expiration of a password and can be unlocked with a command.
STEPS

1

FIND WHICH ACCOUNTS ARE LOCKED WITH THE FOLLOWING QUERY.
SQL > select username,account_status from dba_users where account_status like '%LOCK%';
USERNAME ACCOUNT_STATUS
------------------------------ ----------------
OUTLN EXPIRED & LOCKED
MDSYS EXPIRED & LOCKED
MDDATA EXPIRED User altered.
TIPS
You can also lock an account with the following:
SQL > alter user MDDATA account lock;
User altered.