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 22:13:59 -0800 (PST)
Message-ID: <20030128221313.F4312-100000@megazone23.bigpanda.com> (raw)
In-Reply-To: <E18dlRn-0005Hl-00@israel.diaspora.gen.nz>
On Wed, 29 Jan 2003, Rodger Donaldson wrote:
> > 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.
>
> Sorry; to clarify, it's table.column notation.
I meant to signify what's the behavior? Is it different from a unique
constraint on sites(url)? If so, how?
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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: <20030128221313.F4312-100000@megazone23.bigpanda.com>
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