From: Leif Biberg Kristensen <leif@solumslekt.org>
To: pgsql-sql@postgresql.org
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Subject: Re: DDL problems: Referential issue?
Date: Wed, 4 Nov 2009 21:14:32 +0100
Message-ID: <200911042114.32722.leif@solumslekt.org> (raw)
In-Reply-To: <dcc563d10911041203r61124e04gf22e7f22a8bbd09@mail.gmail.com>
References: <200911041903.36563.leif@solumslekt.org>
<200911041953.11714.leif@solumslekt.org>
<dcc563d10911041203r61124e04gf22e7f22a8bbd09@mail.gmail.com>
On Wednesday 4. November 2009 21.03.26 Scott Marlowe wrote:
> On Wed, Nov 4, 2009 at 11:53 AM, Leif Biberg Kristensen
> > This looks strange to me, but it works:
> >
> > pgslekt=> CREATE TABLE participant_notes (
> > pgslekt(> person_fk INTEGER NOT NULL,
> > pgslekt(> event_fk INTEGER NOT NULL,
> > pgslekt(> part_note TEXT,
> > pgslekt(> PRIMARY KEY (person_fk, event_fk),
> > pgslekt(> FOREIGN KEY (person_fk, event_fk) REFERENCES participants
> > (person_fk, event_fk)
> > pgslekt(> );
> > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index
> > "participant_notes_pkey" for table "participant_notes"
> > CREATE TABLE
>
> Note that this will limit you to one record in your participant notes
> for each record in the participants table.
That's exactly what I want :)
For all practical purposes, the design is equivalent to adding a TEXT column
to the participants table. But as I expect a very small number of notes
compared to the number of rows in the participants table, I prefer to create a
small extra table rather than having a large number of null values in the
participants table. Performance-wise, it probably doesn't matter much. It's
more a matter of taste.
--
Leif Biberg Kristensen
http://solumslekt.org
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To: pgsql-sql@postgresql.org
Cc: leif@solumslekt.org, scott.marlowe@gmail.com
Subject: Re: DDL problems: Referential issue?
In-Reply-To: <200911042114.32722.leif@solumslekt.org>
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