From: Joe <svn@freedomcircle.net>
To: Todd Kennedy <todd.kennedy@gmail.com>
Cc: D'Arcy J.M. Cain <darcy@druid.net>
Cc: pgsql-sql@postgresql.org
Subject: Re: Question about One to Many relationships
Date: Fri, 24 Mar 2006 13:34:34 -0500
Message-ID: <44243BBA.8030802@freedomcircle.net> (raw)
In-Reply-To: <226d83de0603240937o7b5608f9je5179238ee3c9c5a@mail.gmail.com>
References: <226d83de0603240852q54af3512odfce218d69718c8b@mail.gmail.com>
<20060324120142.d3fdf477.darcy@druid.net>
<226d83de0603240937o7b5608f9je5179238ee3c9c5a@mail.gmail.com>
Todd Kennedy wrote:
> They haven't responded me as of yet. There should be a band associated
> with each album -- this is handled in code, but other than that this
> is the only relational db way I can think of to do it.
But if a band can have songs in many albums and an album can have songs
from multiple bands, it's a many-to-many relationship, NOT one-to-many.
Short of the full track design suggested by PFC, you'd normally
implement a many-to-many table as follows:
CREATE TABLE bands_on_album (
band_id integer REFERENCES band (id),
album_id integer REFERENCES albums (id),
PRIMARY KEY (band_id, album_id)
)
This of course precludes the same band being listed twice in a given
album. If you do need that info, then you're really asking for "tracks".
Joe
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To: pgsql-sql@postgresql.org
Cc: svn@freedomcircle.net, todd.kennedy@gmail.com, darcy@druid.net
Subject: Re: Question about One to Many relationships
In-Reply-To: <44243BBA.8030802@freedomcircle.net>
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