| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Jean-Christian Imbeault <jc(at)mega-bucks(dot)co(dot)jp> |
| Cc: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Foreign keys: referencing a REFERENCES doesn7t work? |
| Date: | 2002-08-05 14:14:36 |
| Message-ID: | 20607.1028556876@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Jean-Christian Imbeault <jc(at)mega-bucks(dot)co(dot)jp> writes:
> Seems that pgsql is fine when MOVIES.id references PRODUCTS.id for a
> foreign key but if a table references MOVIES.prod_id for a foreign key
> pgsql cannot go up the reference "tree" and follow what MOVIES.id
> references to see that there really is a unique constraint ...
No, there isn't a unique constraint. Your REFERENCES clause says that
every ID in MOVIES must equal some ID in PRODUCTS; it does *not* say
that two different rows in MOVIES can't reference the same ID in
PRODUCTS. Add a UNIQUE constraint to MOVIES if that's the behavior you
want.
regards, tom lane
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