>A conversation cam up on which is more expensive to the db a computed column or a trigger.
>
>Example was simple Subtract col 4 from col 3. They were non nullable.
>
>So is a trigger more expensive to run vs. a computed column?
>
>My WAG was the CC.
>
>Any takers with some proof? My googles came up with Oracle and DB2 references :(
>
>__Stephen

Stephen,

It seems to me that the fact that a simple computed column is less expensive than a trigger is self-evident. To run a trigger, SQL Server has to set up a private context for the code, including the INSERTED & DELETED tables. Then the trigger code has to be executed and the environment cleaned up.

There has to be at least 100x more work for the server to run a trigger than to compute a column.

You might want to do a search at sql-server-performance.com to see if there is an article or forum post that can help you to substantiate the claim.