From: Michael Paesold <mpaesold@gmx.at>
To: Ross J. Reedstrom <reedstrm@rice.edu>
Cc: Adam Erickson <adamre@cox.net>
Cc: pgsql-sql@postgresql.org
Subject: Re: Rules and Triggers
Date: Wed, 11 Sep 2002 09:28:57 +0200
Message-ID: <002101c25964$e5e4e460$4201a8c0@beeblebrox> (raw)
References: <ALEKKHACBIAEBNBPFKPCGEJNEKAA.adamre@cox.net>
<007c01c25902$9772b940$4201a8c0@beeblebrox>
<20020910232816.GA3983@rice.edu>
Ross J. Reedstrom wrote:
> An important thing to remember about rules vs. triggers: Rules operate
> on an SQL _query_ that involves the table (or view) that the rule is
> attached to, whereas triggers operate on the individual _tuples_ of the
> table they are attached to. Rules act to rewrite the incoming query,
> at the very earliest step: just after parsing, but before planning and
> optimizing. So rules _always_ act first. Triggers act when storage gets
> hit: when the optimizer has choosen a plan, and passes it to the executor
> for, well, execution.
>
> Ross
Thanks alot, again I understand a little bit more.
You're great, guys!
Regards, Michael Paesold
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To: pgsql-sql@postgresql.org
Cc: mpaesold@gmx.at, reedstrm@rice.edu, adamre@cox.net
Subject: Re: Rules and Triggers
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