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From: Erwin <e.smout@myonline.be>
Newsgroups: comp.databases.theory
Subject: Re: SQL deferred constraints (a bit O/T, I know)
Date: Mon, 4 Apr 2011 05:11:20 -0700 (PDT)
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On 4 apr, 07:38, David BL <davi...@iinet.net.au> wrote:
> On Apr 2, 11:21 pm, Erwin <e.sm...@myonline.be> wrote:
>
> > This has been documented before. =A0MVCC and database constraint
> > checking do not fit together.
>
> I thought in normal practice only read only transactions access old
> versions so MVCC doesn't upset constraint checking at all.

Yes. That is probably because DBMS builders are quite aware of the
problem.

The OP, however, didn't seem to be (as also evidenced by his own
reply).