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From: Jeff Davis on 24 May 2010 23:25
On Sat, 2010-05-22 at 01:02 +0300, Marko Tiikkaja wrote:
> On 5/21/10 11:47 PM +0300, Jeff Davis wrote:
> > It also allows you to enforce the constraint that only one tuple exists
> > in a table by doing something like:
> >
> > create table a
> > (
> > i int,
> > exclude using gist (i with<>),
> > unique (i)
> > );
>
> FWIW, this is achievable a lot more easily:
> CREATE UNIQUE INDEX "a_single_row" ON a ((1));
>

Yes, you're right. Also, neither of us accounted for NULLs, so I suppose
a NOT NULL is necessary as well.

I think the original case (same values only) is potentially useful
enough that we should support it.

Regards,
Jeff Davis


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