Way to identify which row is being locked

• DBA_BLOCKERS -- Shows non-waiting sessions holding locks being waited on
• DBA_DDL_LOCKS -- Shows all DDL locks held or being requested
• DBA_DML_LOCKS -- Shows all DML locks held or being requested
• DBA_LOCK_INTERNAL -- Displays one row for every lock or latch held or being requested
• DBA_LOCKS -- Shows all locks or latches held or being requested
• DBA_WAITERS -- Shows all sessions waiting on, but not holding waited for locks

The DBA_LOCK_INTERNAL view is best to show locks for a specific user, and you can specify the query in the form:

SELECT
   NVL(b.username,'SYS') username,
   session_id,lock_type,mode_held,
   mode_requested,lock_id1,lock_id2
FROM
   sys.dba_lock_internal a,
   sys.v_$session b
where  . . .