From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
To: Rodger Donaldson <rodgerd@diaspora.gen.nz>
Cc: pgsql-sql@postgresql.org
Subject: Re: Cross-table constraints
Date: Tue, 28 Jan 2003 22:03:02 -0800 (PST)
Message-ID: <20030128215859.W4312-100000@megazone23.bigpanda.com> (raw)
In-Reply-To: <20030128070514.GB7146@diaspora.gen.nz>
On Tue, 28 Jan 2003, Rodger Donaldson wrote:
> Now, adding a UNIQUE constraint on the pk for add_queue weeds out
> dupes there. However, attempting to add a cross-table UNIQUE check
> with:
>
> alter table add_queue add constraint add_queue_no_dupe_sites unique
> (sites.url);
> ERROR: parser: parse error at or near "."
>
> ,,,fails. Foreign key constraints will only require a match (of one
> sort or another) in the foreign table, according to the postgresql 7.2
> documentation, and do not have an option to require no match.
>
> Am I missing something obvious (syntax for UNIQUE, for example), or
> trying to do something that just doesn't work that way?
I'm not sure what a unique constraint on sites.url on table add_queue
is supposed to mean precisely. You can probably come pretty close by
making a set of triggers on both tables however.
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To: pgsql-sql@postgresql.org
Cc: sszabo@megazone23.bigpanda.com, rodgerd@diaspora.gen.nz
Subject: Re: Cross-table constraints
In-Reply-To: <20030128215859.W4312-100000@megazone23.bigpanda.com>
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