From: Itai Zukerman <zukerman@math-hat.com>
To: Andreas Tille <tillea@rki.de>
Cc: PostgreSQL SQL <pgsql-sql@postgresql.org>
Subject: Re: Foreign key problem
Date: 25 Jun 2001 10:07:21 -0400
Message-ID: <878zig1wme.fsf@matt.w80.math-hat.com> (raw)
In-Reply-To: <Pine.LNX.4.33.0106250933390.905-100000@wr-linux02.rki.ivbb.bund.de>
References: <Pine.LNX.4.33.0106250933390.905-100000@wr-linux02.rki.ivbb.bund.de>
Je Mon, 25 Jun 2001 09:34:01 +0200 (CEST),
Andreas Tille <tillea@rki.de> scribis:
> CREATE TABLE ResKulturDetail
> (
> IdLabNr int,
> IdIndex smallint
> );
>
> CREATE TABLE ResKulturDetailDay
> (
> IdLabNr int,
> IdIndex smallint
> );
>
> CREATE INDEX IX_IdLabNr_KulturDetail ON ResKulturDetail(IdLabNr) ;
>
> ALTER TABLE ResKulturDetailDay ADD CONSTRAINT FK_ResKulturDetailDay
> FOREIGN KEY (IdLabNr,IdIndex)
> REFERENCES ResKulturDetail (IdLabNr,IdIndex) ;
> Can anybody explain, why the foreign key constraint fails?
According to the documentation for CREATE TABLE:
In addition, the referenced columns are supposed to be the columns
of a UNIQUE constraint in the referenced table, however Postgres
does not enforce this.
Well, it looks like PostgreSQL *does* enforce it. Try it with:
CREATE UNIQUE INDEX IX_IdLabNr_KulturDetail
ON ResKulturDetail(IdLabNr, IdIndex) ;
I'm not sure why this restriction is necessary...
--
Itai Zukerman <http://www.math-hat.com/~zukerman/;
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To: pgsql-sql@postgresql.org
Cc: zukerman@math-hat.com, tillea@rki.de
Subject: Re: Foreign key problem
In-Reply-To: <878zig1wme.fsf@matt.w80.math-hat.com>
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