From: | Don Baccus <dhogaza(at)pacifier(dot)com> |
---|---|
To: | Jan Wieck <wieck(at)debis(dot)com> |
Cc: | Jan Wieck <wieck(at)debis(dot)com>, PostgreSQL HACKERS <pgsql-hackers(at)postgreSQL(dot)org> |
Subject: | Re: [HACKERS] FOREIGN KEY !!!!! |
Date: | 2000-02-05 20:47:42 |
Message-ID: | 3.0.1.32.20000205124742.00f991e0@mail.pacifier.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
At 09:30 PM 2/5/00 +0100, Jan Wieck wrote:
>> o Under RESTRICT, by contrast, the system realizes "ahead of
>> time" that row R2 exists and will violate the constraint if
>> R1 is deleted, and so rejects the DELETE out of hand.
> That'd mean in last consequence, that RESTRICT actions aren't
> DEFERRABLE, while the rest of their constraint definition is!
That's how I read it, too. Pardon me while I run off to vomit in
the toilet.
> Anyway, cannot work with the actual implementation of the
> trigger queue, so we could either make RESTRICT and NO ACTION
> identical (except for different ERROR messages), or leave the
> SQL3 RESTRICT out of 7.0 while changing NO ACTION to fire the
> message.
> I'd prefer to have them identical in 7.0, because according
> to Date they have no semantic difference, so it'll buy us
> little if we complicate the trigger stuff more than required
> right now.
If others on the list agree, I think this is an excellent idea. I
see no semantic difference that the application will see, either,
other than a difference in execution time.
Raising the exception before the delete or update seems more an efficiency
hack than anything, i.e. it's much less expensive to short-circuit the
delete/update rather than finish it, check afterwards, and roll it
back.
- Don Baccus, Portland OR <dhogaza(at)pacifier(dot)com>
Nature photos, on-line guides, Pacific Northwest
Rare Bird Alert Service and other goodies at
http://donb.photo.net.
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