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Re: Trigger question

From: Richard Huxton <dev(at)archonet(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Harald Fuchs <hf118(at)protecting(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Trigger question
Date: 2004-01-20 19:05:46
Message-ID: 200401201905.46699.dev@archonet.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Tuesday 20 January 2004 16:42, Tom Lane wrote:
> Harald Fuchs <hf118(at)protecting(dot)net> writes:
> > Why?  If the underlying table has a primary key, finding corresponding
> > pairs is trivial; if there isn't, it's impossible.
>
> Exactly.  Nonetheless, the correspondence exists --- the UPDATE
> definitely updated some particular row of the OLD set into some
> particular one of the NEW set.  If the trigger API makes it impossible
> to reconstruct the matchup, the API is broken.

Perhaps they should be cursors? The only sensible way I can think of working 
with them would be:
1. count how many rows affected
2. step through one row at a time, doing something.

I suppose there might be cases where you'd want to GROUP BY... which would 
mean you'd need some oid/row-id added to a "real" recordset.

-- 
  Richard Huxton
  Archonet Ltd

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