From: Tom Lane <tgl@sss.pgh.pa.us>
To: Stephan Szabo <sszabo@megazone.bigpanda.com>
Cc: Markus Bertheau <twanger@bluetwanger.de>
Cc: Richard Huxton <dev@archonet.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: multi column foreign key for implicitly unique columns
Date: Tue, 17 Aug 2004 11:38:14 -0400
Message-ID: <4876.1092757094@sss.pgh.pa.us> (raw)
In-Reply-To: <20040817081306.J61699@megazone.bigpanda.com>
References: <1092734724.2627.4.camel@dicaprio.akademie1.de>
<4121D55D.1040105@archonet.com>
<20040817072443.S60684@megazone.bigpanda.com>
<4307.1092753995@sss.pgh.pa.us>
<1092754658.2627.32.camel@dicaprio.akademie1.de>
<20040817080425.U61699@megazone.bigpanda.com>
<1092755530.2627.36.camel@dicaprio.akademie1.de>
<20040817081306.J61699@megazone.bigpanda.com>
Stephan Szabo <sszabo@megazone.bigpanda.com> writes:
> ... It sounds like it'd be a pain at best.
Also, that would directly violate the SQL spec's model of dependencies,
with possibly unpleasant consequences. The current implementation does
exactly what SQL says to do. I cite from SQL99 11.99 DROP CONSTRAINT:
3) If TC is a unique constraint and RC is a referential constraint
whose referenced table is T and whose referenced columns are the
unique columns of TC, then RC is said to be dependent on TC.
...
6) If RESTRICT is specified, then:
a) No table constraint shall be dependent on TC.
NOTE 195 - If CASCADE is specified, then any such dependent
object will be dropped by the effective execution of the
<alter table statement> specified in the General Rules of this
Subclause.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, sszabo@megazone.bigpanda.com, twanger@bluetwanger.de, dev@archonet.com
Subject: Re: multi column foreign key for implicitly unique columns
In-Reply-To: <4876.1092757094@sss.pgh.pa.us>
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