Re: Question about One to Many relationships
От | Todd Kennedy |
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Тема | Re: Question about One to Many relationships |
Дата | |
Msg-id | 226d83de0603241036n3795047fy412f076f23f7be1c@mail.gmail.com обсуждение исходный текст |
Ответ на | Question about One to Many relationships ("Todd Kennedy" <todd.kennedy@gmail.com>) |
Список | pgsql-sql |
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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