Re: Hashing for DISTINCT or GROUP BY in SQL

From: Erwin <>
Date: Mon, 18 Oct 2010 04:35:10 -0700 (PDT)
Message-ID: <>

On 18 okt, 03:03, paul c <anonym..._at_not-for-mail.invalid> wrote:
> For example, I've often wondered 'where or what is the implementation
> theory of constraints?'.

The 1990 Ceri/Widom paper and the more recent Martinenghi phd thesis are, as far as I'm aware, the reference.

You also know already that SIRA_PRISE allows declaration of both database and assignment constraints of arbitrary complexity. So I take it you are aware that there is an implementation for what you mention. Now, being the author of that implementation, I would never claim that I developed a 'theory' to achieve that. In fact, I wonder what the hell a 'theory of implementation' would look like. I'm tempted to suggest it would look like a 'theory of brick masoning', or a 'theory of mixing flour and water for bread baking'. Sounds odd, I must say. Received on Mon Oct 18 2010 - 13:35:10 CEST

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