Re: permissions & foreign keys

From: Jan Wieck <janwieck(at)Yahoo(dot)com>
To: Tamsin <tg_mail(at)bryncadfan(dot)co(dot)uk>
Cc: "Pgsql-General(at)Postgresql(dot)Org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: permissions & foreign keys
Date: 2000-09-04 14:49:38
Message-ID: 200009041449.JAA02302@jupiter.jw.home
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Tamsin wrote:
>
> I don't really see why it wants to update feedback_type? Can anyone tell me
> what I'm doing wrong, or will I just have to grant update on feedback_type
> (and all other tables referenced by FKs)?
>

It doesn't want to update it. It just does the SELECT ... FOR
UPDATE to lock the now referenced row. Doing it without a
lock would make it possible, that just after your backend
checked that the PK row exists but before you got a chance to
commit, another backend could delete that PK without seeing
your just inserted reference. End would be a violated FK
constraint.

The bug here is, that doing a SELECT ... FOR UPDATE already
requires UPDATE permissions. The correct solution would be to
require a REFERENCES privilege for the owner of the
referencing table. But we don't have that up to now.

Maybe I can do something about it for 7.1.

Jan

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