From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
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To: | Matt Clark <matt(at)ymogen(dot)net> |
Cc: | 'Rod Taylor' <pg(at)rbt(dot)ca>, 'Ulrich Wisser' <ulrich(dot)wisser(at)relevanttraffic(dot)se>, 'gnari' <gnari(at)simnet(dot)is>, 'Postgresql Performance' <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: insert |
Date: | 2004-08-13 16:31:34 |
Message-ID: | 20040813163134.GA3743@wolff.to |
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Thread: | |
Lists: | pgsql-performance |
On Fri, Aug 13, 2004 at 17:17:10 +0100,
Matt Clark <matt(at)ymogen(dot)net> wrote:
> > > It is likely that you are missing an index on one of those foreign
> > > key'd items.
> >
> > I don't think that is too likely as a foreign key reference
> > must be a unique key which would have an index.
>
> I think you must be thinking of primary keys, not foreign keys. All
> one-to-many relationships have non-unique foreign keys.
The target of the reference needs to have at least a unique index.
I am not sure if it needs to actually be declared as either a unique
or primary key, though that is the intention.
The records doing the referencing don't need (and normally aren't)
unique.
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