ADD/ENABLE constraint exception like ORA-02437, ORA-02299 etc
Today while working on one assignment I came across situation where I have to enable a unique key constraint on the table which some one disabled and forget due to which many duplicate records get entered and started creating problem for the application.
Now challenge is to find out all those records there are ways to find duplicates by writing some queries but this is easiest and faster way by using Oracle Exceptions table.