Darn, that's what I was afraid of (no quick solution).

I allready have this (working) "INSTEAD OF" trigger:

DECLARE @company_id INT

IF OBJECT_ID('tempdb..#cyn_vars') IS NOT NULL

BEGIN

SELECT @company_id = (SELECT CAST(param_value AS INT) FROM...

@ steve jones: how can a stored procedure help me? I can't use the return value of a stored procedure as default constraint, can I?

PS: I know what value to...