Re: Question about One to Many relationships

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От Todd Kennedy
Тема Re: Question about One to Many relationships
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Msg-id 226d83de0603241036n3795047fy412f076f23f7be1c@mail.gmail.com
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Ответ на Question about One to Many relationships  ("Todd Kennedy" <todd.kennedy@gmail.com>)
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We're not concerned with the track info.  This is a listing of album
information, hence the one to many relationship between the album and
the artist.

and for the record, i should correct myself.  he said it was "bad" not "wrong".

but i hadn't given him all the details.

But.  Yes.  Thank you all for your help.

On 3/24/06, Joe <svn@freedomcircle.net> wrote:
> 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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