“Ideas pull the trigger, but instinct loads the gun.”
The Fundamentals of Triggers
1. A Trigger is an Event driven maintenance operation (Object Type ‘G’)
2. The event is caused (Trigger Fired) by one or more modifications to a table
3. The Original Modification, the TRIGGER, and all subsequent triggers constitute a Single Transaction
4. The SQL and all Triggers associated must each work or all are Rolled Back
5. The user's initial SQL maintenance request that causes a row to change in a table and then causes a trigger to fire (execute) can be: INSERT, UPDATE, DELETE or INSERT/SELECT (SELECT will NOT work to fire a Trigger)
6. Once a Trigger fires, it can perform SQL such as INSERT, UPDATE, DELETE, ...