| From: | David Wheeler <david(at)kineticode(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Neil Conway <neilc(at)samurai(dot)com>, Jan Wieck <JanWieck(at)yahoo(dot)com> |
| Subject: | Re: DO INSTEAD and conditional rules |
| Date: | 2005-04-26 06:05:56 |
| Message-ID: | b2fef70cdda15b007cbb4fd1598dcd48@kineticode.com |
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| Thread: | |
| Lists: | pgsql-hackers |
On Apr 25, 2005, at 11:00 PM, Tom Lane wrote:
> DO INSTEAD means that the *original* query will not execute; it does
> not suppress actions produced by other rules.
Ah!
> If we did not define
> it that way, I think your example would have to error out --- how
> would you choose which INSTEAD rule wins?
The documentation says that they evaluate in alphabetical order by
name. So I would expect that the first one to have its WHERE statement
evaluate to true would short-circuit the execution of the remaining
rules.
Regards,
David
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