another trigger question

Is trigger based on table level or can I define it on certain fields level
against a table?A trigger is defined on an INSERT, UPDATE or DELETE statement against a
table (in fact you can write a special kind (INSTEAD OF trigger) against
views now too). INSERTs & DELETEs work on an entire row so it doesn't make
much sense to do stuff at the column level there, but within a trigger on an
UPDATE operation you can define specific behaviour if certain columns on the
table are changed with the IF UPDATE() clause (it works with INSERT triggers
too but makes less sense). For example,
CREATE TRIGGER MyInsertTrigger on dbo.MyTable
FOR UPDATE AS
-- Check to see if a specific column has changed
if UPDATE(MyCol)
BEGIN
-- Do some SQL stuff in here because the column we're interested
in has changed
END
-- Do other general UPDATE trigger stuff
GO
SQL Books Online has more info on it in the "Creating and Maintaining
Databases" | "Enforcing Business Rules with Triggers" | "Creating a Trigger"
| "Programming Triggers" section.
HTH.
Cheers,
Mike
""Allen Iverson"" <no_spam@.bk.com> wrote in message
news:ud8HZU20EHA.3584@.TK2MSFTNGP11.phx.gbl...
> Is trigger based on table level or can I define it on certain fields level
> against a table?
>