On Thu, 10 Jun 2004, mike wrote:
> On Thu, 2004-06-10 at 17:03, Uwe C. Schroeder wrote:
> > Try to add a null value to lk_sub_con.type - or any value that's not in
> > lk_sort_of_contact. Postgres will throw an error.
>
> this is the problem - it doesnt if I put a null in (the refernced column
> has no nulls)
NULLs in a referencing column are a special case in the spec. For a
single column key, a NULL is considered to pass the constraint. For
multiple column keys it depends on the match type.