 <p>Try to execute this first ,and check whether anyone from <code>other session</code> or <code>your session</code> put a lock on that table .If <code>you</code> have put a lock on that table,try to do <code>commit/rollback</code> .If <code>someone else</code> put a lock ,ask <code>him/her</code> or if you have rights <code>kill his session</code> .And then drop the table.</p> <pre><code> select session_id "sid",SERIAL# "Serial", substr(object_name,1,20) "Object", substr(os_user_name,1,10) "Terminal", substr(oracle_username,1,10) "Locker", nvl(lockwait,'active') "Wait", decode(locked_mode, 2, 'row share', 3, 'row exclusive', 4, 'share', 5, 'share row exclusive', 6, 'exclusive', 'unknown') "Lockmode", OBJECT_TYPE "Type" FROM SYS.V_$LOCKED_OBJECT A, SYS.ALL_OBJECTS B, SYS.V_$SESSION c WHERE A.OBJECT_ID = B.OBJECT_ID AND C.SID = A.SESSION_ID ORDER BY 1 ASC, 5 Desc </code></pre>