Re: FOREIGN KEYS vs PERFORMANCE

On Wed, Apr 12, 2006 at 07:45:17AM -0700, Craig A. James wrote:
> All good advice, but... there are no absolutes in this world.
> Application-enforced referential integrity makes sense if (and probably
> ONLY if):
>
> 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.

> 2. If your application crashes and leaves a mess, it's not a catastrophe,
> and you have a good way to clean it up. For example, a bank shouldn't do
> this, but it might be OK for a computer-aided-design application, or the
> backend of a news web site.
>
> 3. You have application-specific knowledge about when you can skip
> referential integrity and thereby greatly improve performance. For
> example, you may have batch operations where large numbers of rows are
> temporarily inconsistent.
>
> If your application doesn't meet ALL of these criteria, you probably should
> use the database for referential integrity.
>
> Craig
>
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--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
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