There is no column level or row level trigger. A trigger is defined according to the operation on the table, so you can have triggers for insert, update and delete. The trigger is fired only once and won't be fired for each row that was affected nor for each column. That means that if I issued an update statement on a table that has an update trigger, and the statement updated 4 columns in 20 rows, the trigger will run only once. If it is important for me to base trigger's operation on the columns that were modified, it is up to me to check in the trigger's code which column was modified.

Adi