Re: Foreign key constraint accepted even when not same - Mailing list pgsql-general

From Stephan Szabo
Subject Re: Foreign key constraint accepted even when not same
Date
Msg-id 20030924193348.Y67854@megazone.bigpanda.com
Whole thread Raw
In response to Re: Foreign key constraint accepted even when not same  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-general
On Wed, 24 Sep 2003, Bruce Momjian wrote:

> Tom Lane wrote:
> > Stephan Szabo <sszabo@megazone.bigpanda.com> writes:
> > > On Mon, 22 Sep 2003, Jean-Christian Imbeault wrote:
> > >> Is it right for postgres to accept a foreign key constraint when the
> > >> type of the field is not the same as that of the foreign key?
> >
> > > IIRC in SQL92 it's said that they need to be the same type, but in SQL99
> > > it says that the two types must be comparable.  We basically implement the
> > > latter, basically using the existance of a usable equality operator as the
> > > determination of comparable.
> >
> > Note however that performance may be poor with a cross-type foreign key
> > reference, if the planner is unable to figure out how to use an index
> > for the check queries.
>
> Didn't we agree to throw a NOTICE in cases of a mismatch?  (I think
> Peter agreed to a NOTICE but not a WARNING)  Is that completed?

Did that get decided upon?  In any case, I don't think domains were talked
about.  Should it be decided upon the base type of the domain(s) involved
or just that the final types are different?

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