title: Insert Update trigger how to determine if insert or update
body: <p>I need to write an Insert, Update Trigger on table A which will delete all rows from table B whose one column (say Desc) has values like the value inserted/updated in the table A's column (say Col1). How would I go around writing it so that I can handle both Update and Insert cases. How would I determine if the trigger is executed for an update or insert.</p>