From: Leif Biberg Kristensen <leif@solumslekt.org>
To: pgsql-sql@postgresql.org
Subject: Re: DDL problems: Referential issue?
Date: Wed, 4 Nov 2009 19:36:15 +0100
Message-ID: <200911041936.15292.leif@solumslekt.org> (raw)
In-Reply-To: <dcc563d10911041024s67a3c313w1ed90c415840c2f7@mail.gmail.com>
References: <200911041903.36563.leif@solumslekt.org>
<dcc563d10911041024s67a3c313w1ed90c415840c2f7@mail.gmail.com>
On Wednesday 4. November 2009 19.24.29 Scott Marlowe wrote:
> You're referencing a single column, which does not have a unique key
> on it. Being part of a two column unique PK index doesn't count, as
> you could have an entry where one column or the other repeats on its
> own while the other column changes. You might want the syntax:
>
> FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn
> [, ... ] )
>
> where you FK a pair of columns to a pair of other columns.
Thank you very much!
pgslekt=> CREATE TABLE participant_notes (
pgslekt(> person_fk INTEGER,
pgslekt(> event_fk INTEGER,
pgslekt(> part_note TEXT,
pgslekt(> FOREIGN KEY (person_fk, event_fk) REFERENCES participants
(person_fk, event_fk)
pgslekt(> );
CREATE TABLE
I'd missed that particular syntax.
This table is now without a primary key, but is that a problem? I don't expect
it to grow beyond maybe a few thousand rows.
--
Leif Biberg Kristensen
http://solumslekt.org
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Cc: leif@solumslekt.org
Subject: Re: DDL problems: Referential issue?
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