>Cetin,
>
>sorry this is not so good for me, because i want to put as many business rules as can be in the database.
>have you got an another idea?
>
>Ivan

Ivan,
How can you do in valid then ? It would look like almost the same :

if !IsValidData(this.Value, this.Controlsource) && IsValidData stored proc
  nodefault
* messages 
  this.SetFocus()
endif

Cetin