Message-ID: <20030424211805.22526.qmail@celery.tssi.com>
From: nolan@celery.tssi.com
Subject: Re: [SQL] rewriting values with before trigger
To: gearond@cvc.net
Date: Thu, 24 Apr 2003 16:18:05 -0500 (CDT)
Cc: xzilla@users.sourceforge.net (Robert Treat),
	josh@agliodbs.com (Josh Berkus),
	pgsql-general@postgresql.org (pgsql-general@postgresql.org),
	pgsql-sql@postgresql.org
In-Reply-To: <3EA836AF.8060704@cvc.net> from "Dennis Gearon" at Apr 24,
	2003 12:10:39 PM
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> OR, deliberately name your triggers with alphanumerical prefixes that 
> forces them to fire in a certain order, and making the trigger that 
> does the conversion fire first?

The SQL 99 standard mandates that triggers fire the order defined, though
the docs say pgsql does it in alphabetical order, possibly because that 
was easier to implement.  

It is probably better to assume that in any given situation they will fire 
in a random order and sequence events yourself when necessary.

That may mean throwing the '' into NULL logic into every trigger for that
table, though there are probably more elegant ways to achieve that result.

If God (or Codd?) had meant us to enable triggers to fire in a particular 
order, there would be a 'firing order nnnn' sequencing parameter in the 
standard.

--
Mike Nolan