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From: Richard Huxton <dev@archonet.com>
Organization: Archonet Ltd
To: ed despard <despareg@clarkson.edu>, pgsql-general@postgresql.org
Subject: Re: rules question
Date: Wed, 30 Apr 2003 10:26:51 +0100
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On Wednesday 30 Apr 2003 5:00 am, ed despard wrote:
> hi, i have a table named pursuit which has no data in it, currently to
> get data for the table i have a function that i call like: select *
> from pursuit_select_function(raceid), but i put in the raceid that im
> selecting for.  i would like to be able to treat this table like a view
> and make a query like select * from pursuit where raceid=3D9 or somthing
> and have a rule rewrite this into the function call. is there a way to
> have a rule that rewrites the query based on the qualifier of the query?

I think you're out of luck here.

For "where raceid=3D9" it's easy enough - just call "function(9)".
What if someone uses "where raceid in (7,8,9)" - does the planner write tha=
t=20
as "function(7) or function (8) or function(9)" and how does that interact=
=20
with your side-effects?

> the reason im not just using a normal view is that i have a sequence
> that needs to be reset before each select, so the
> pursuit_select_function resets the sequence and does the select query.

I was thinking you could create a rule with multiple queries for the action=
,=20
but unfortunately that's not supported for ON SELECT rules (according to my=
=20
docs). If it was, you could reset the sequence as the first query, then do=
=20
your processing for the second.

I take it you're using the sequence to number output rows?
--=20
  Richard Huxton