On Wednesday 12 September 2007 15:56:13 Josh Trutwin wrote: > If I create an ON UPDATE trigger run on each row after update, does > the trigger fire only on rows affected by the update or for all rows? > > For example: > > CREATE TRIGGER my_update_trigger > AFTER UPDATE ON my_table > FOR EACH ROW > EXECUTE PROCEDURE my_update_proc; > > UPDATE my_table SET my_val = my_val * 2; > > Will the trigger fire on rows that have NULL for my_val? I haven't tested what you asked (you can do that easily), but if this is your concern and if you have a huge table you might want to add a WHERE clause: "WHERE my_val IS NOT NULL". -- Jorge Godoy <jgodoy@xxxxxxxxx> ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
