Re: SET CONSTRAINTS and like named constraints

On Thu, 4 Sep 2003, Bruce Momjian wrote:

> Stephan Szabo wrote:
> >
> > It looks like that right now if you have multiple constraints
> > with the same name on different tables and some are deferrable
> > and some are not, SET CONSTRAINTS "name" DEFERRED will fail when
> > it reaches the not deferrable constraint. Is this the behavior
> > we want, or do we want it to defer the deferrable ones with that
> > name and possibly warn that some were not deferrable?
>
> We have this TODO:
>
> * Allow SET CONSTRAINTS to be qualified by schema/table

I'd think the above is in addition to the TODO item. We should define the
behavior for unqualified constraint names.

I can see a few possibilities for the behavior of SET CONSTRAINTS DEFERRED
a) The current behavior. If an unqualified constraint name matches
multiple constraints and any of those constraints are non-deferrable it is
an error, otherwise all matching constraints are deferred.
b) The above behavior. If an unqualified constraint name matches
multiple constraints and all of those constraints are non-deferrable it is
an error, otherwise all matching deferrable constraints are deferred
(possibly with a warning if any are non-deferrable).
c) If an unqualified constraint name matches multiple constraints it is
an error (presumably for set ... immediate as well).

a is the easiest to do probably since it's what's there right now. It's
also compatible with how we do things now. b is closer to what I think
people might expect it to do and allows more than what we do now (so
presumably the only people that would be bitten by it on upgrade are
people that are getting errors right now). c is the "safest" option for
preventing someone from doing something they don't want, but is the least
compatible with what we have now.