Re: Allow foreign keys to reference a superset of unique columns

On Fri, 10 Jun 2022 at 16:14, Peter Eisentraut
<peter(dot)eisentraut(at)enterprisedb(dot)com> wrote:
>
> On 10.06.22 05:47, David Rowley wrote:
> >> I think this should be referring to constraint name, not an index name.
> > Can you explain why you think that?
>
> If you wanted to specify this feature in the SQL standard (I'm not
> proposing that, but it seems plausible), then you need to deal in terms
> of constraints, not indexes. Maybe referring to an index directly could
> be a backup option if desired, but I don't see why that would be
> necessary, since you can easily create a real constraint on top of an index.

That's a good point, but, if we invented syntax for specifying a
constraint name, would that not increase the likelihood that we'd end
up with something that conflicts with some future extension to the SQL
standard?

We already have USING INDEX as an extension to ADD CONSTRAINT.

David