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From: terry@greatgulfhomes.com
To: "'Jan Wieck'" <janwieck@yahoo.com>,
	"'Achilleus Mantzios'" <achill@matrix.gatewaynet.com>
Cc: <pgsql-general@postgresql.org>, <pgsql-sql@postgresql.org>
Subject: Re: [SQL] VIEWs and FOREIGN keys
Date: Mon, 10 Jun 2002 14:49:33 -0400
Message-ID: <002801c210af$9088c980$2766f30a@development.greatgulfhomes.com>
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I would just like to elaborate, and clarify if my understanding is correct:

The implication of below is that you need a trigger in the foreign key
target table on the DELETE event, so the foreign key table only lets you
delete a row if there are no other tables refering to the key you want to
delete.

Views cannot have triggers, hence cannot have a DELETE trigger, therefore
that is why the view cannot be a foreign key target table.

Terry Fielder
Network Engineer
Great Gulf Homes / Ashton Woods Homes
terry@greatgulfhomes.com

> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Jan Wieck
> Sent: Monday, June 10, 2002 1:20 PM
> To: Achilleus Mantzios
> Cc: pgsql-general@postgresql.org; pgsql-sql@postgresql.org
> Subject: Re: [GENERAL] [SQL] VIEWs and FOREIGN keys
>
>
> Achilleus Mantzios wrote:
> >
> > can someone have a foreign key constraint that references
> > a view??
>
>     No,  and  this is not planned either. Remember that it is not
>     only required for referential integrity to  check  if  a  key
>     exists  on  INSERT  or  UPDATE  to the referencing table. The
>     system must guarantee that you cannot  remove  existing  keys
>     while  they  are  referenced  (or  more  precise  perform the
>     requested referential action).
>
>
> Jan
>
> --
>
> #=============================================================
> =========#
> # It's easier to get forgiveness for being wrong than for
> being right. #
> # Let's break this rule - forgive me.
>          #
> #==================================================
> JanWieck@Yahoo.com #
>
>
>
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