Wise to use trigger to update another table?
Mostly Copy/Pasting my response from this question on stackoverflow

Triggers can be very alluring, when you first start using them they seem like a magic bullet to all kinds of problems. But, they make "magic" stuff happen, if you don't know the database inside out, it can seem like really strange things happen (such as inserts into other tables, input data changing, etc). Before implementing things as a trigger I'd seriously consider instead enforcing the use of an API around the schema (preferably in the database, but outside if you can't).

Some things I'd still use triggers for


Keeping track of "date_created" and "date_last_edited" fields
Inserting "ID"'s (in oracle, where there is no auto id field)
Keeping change history


Things you wouldn't want to use triggers for


business rules/logic
anything which connects outside of the database (eg a webservice call)
Access control
Anything which isn't transactional ( anything you do in the trigger MUST be able to rollback with the transaction )