Edit module does not have validation tab

I have a module with 4 fields id1, id2, name, address. a record is unique when it is distinct combination is id1 and id2 together.
i am trying to set this up and

  1. i dont see a validation tab, i only see unique values tab
  2. though i add id1 and id2 both under unique contraint #1 it still looks for uniqueness in id1 and id2 separately.
    please let me know how i can get around this.

Since this is a more complex case I suggest you handle this using workflows. Where you can do extensive validation.

What to do in the workflow:

  1. Check if there exists a record with the same combination of ids (use a record list with a prefilter to determine that)
  2. Raise an error or save based on if value is not distinct