On Sun, 2011-01-23 at 16:13 -0500, Tom Lane wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
> > You can add an FK without an initial check, but the FK is enforced for
> > all further DML changes.
>
> I seem to recall pointing out upthread that the FK check triggers are
> designed on the assumption that the constraint does hold currently.
> Has any analysis been done on exactly how badly they'll fail when it
> doesn't hold? I remain unconvinced that this behavior is desirable.
If you mean RESTRICT relationships, then yes.
I haven't foreseen other problems myself. What other ideas or risks
would you like me to confirm or deny for you?
-- Simon Riggs http://www.2ndQuadrant.com/books/PostgreSQL Development, 24x7 Support, Training and Services