Message-ID: <443D3A9C.40106@modgraph-usa.com>
Date: Wed, 12 Apr 2006 10:36:28 -0700
From: "Craig A. James" <cjames@modgraph-usa.com>
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To: "Jim C. Nasby" <jnasby@pervasive.com>
CC: PFC <lists@peufeu.com>, Michael Glaesemann <grzm@myrealbox.com>,
	Rodrigo Sakai <rodrigo.sakai@zanthus.com.br>,
	pgsql-performance@postgresql.org
Subject: Re: FOREIGN KEYS  vs  PERFORMANCE
References: <001301c65d9c$08884ef0$4700a8c0@TREEZANTHUS>
	<72C39159-1A4B-4595-A978-1DF57AD42527@myrealbox.com>
	<op.s7vv4ex2cigqcu@apollo13> <443D127D.2070601@modgraph-usa.com>
	<20060412153951.GH49405@pervasive.com>
In-Reply-To: <20060412153951.GH49405@pervasive.com>
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Jim C. Nasby wrote:
>>1. You have only one application that modifies the data.  (Otherwise, you 
>>have to duplicate the rules across many applications, leading to a 
>>code-maintenance nightmare).
> 
> You forgot something:
> 
> 1a: You know that there will never, ever, ever, ever, be any other
> application that wants to talk to the database.
> 
> I know tons of people that get burned because they go with something
> that's "good enough for now", and then regret that decision for years to
> come.

No, I don't agree with this.  Too many people waste time designing for "what if..." scenarios that never happen.  You don't want to be dumb and design something that locks out a foreseeable and likely future need, but referential integrity doesn't meet this criterion.  There's nothing to keep you from changing from app-managed to database-managed referential integrity if your needs change.

Design for your current requirements.


Let us be of good cheer, remembering that the misfortunes hardest to bear are 
those which never happen.		- James Russell Lowell (1819-1891)

Therefore do not be anxious about tomorrow, for tomorrow will be anxious for 
itself.  Let the day's own trouble be sufficient for the day.
					- Matthew 6:34

Craig