Okay, thanks. That helps me understand it better. But , if you are using it in a trigger that fires AFTER an INSERT or UPDATE,...

That means that if I have a table Testing with col1, col2, col3, col4, and I did an insert like so:

INSERT INTO Testing(col1, col2, col3, col4)

VALUES('a', 'b','','d')

and the update() tests...

So when will an update() be false?