Re: 9.6 Feature help requested: Inclusion Constraints

On Tue, Feb 10, 2015 at 09:47:22PM -0500, Peter Eisentraut wrote:
> On 2/9/15 3:12 AM, Jeff Davis wrote:
> > On Sat, 2015-02-07 at 16:08 -0800, Jeff Davis wrote:
> >> I believe Inclusion Constraints will be important for postgres.
> >
> > I forgot to credit Darren Duncan with the name of this feature:
> >
> > http://www.postgresql.org/message-id/4F8BB9B0.5090708@darrenduncan.net
>
> I think it would be confusing to name something inclusion constraint
> that is not somehow the opposite of an exclusion constraint.

To my view, this opposition is there.

In both cases, permission for a tuple to exist is based on another
other tuple's presence with some generalized equality criterion. In
the exclusion case, it's prevented. In the inclusion case, it's
required.

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
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