If what are the DML events an existing trigger is handling, you can use the catalog view, sys.trigger_events. You need to join sys.trigger_events and sys.triggers to get a better list as shown in this tutorial example:

USE GlobalGuideLineDatabase

GO

SELECT t.name, e.type, e.type_desc

FROM sys.trigger_events AS e, sys.triggers AS t

WHERE e.object_id = t.object_id

GO

name   type type_desc

-------------- ------ ---------

dml_message 1 INSERT

dml_message 2 UPDATE

dml_message 3 DELETE

new_user  1 INSERT

(4 row(s) affected)

The list clearly shows that dml_message handles 3 events: INSERT, UPDATE and DELETE.