Re: Examples of SQL anomalies?

From: JOG <>
Date: Mon, 7 Jul 2008 13:21:20 -0700 (PDT)
Message-ID: <>

On Jul 5, 1:09 pm, "David Cressey" <> wrote:
> "Marshall" <> wrote in message
> > What can be meaningfully asked is determined by the schema.
> > If the schema specifies that the weight attribute is nullable,
> > then the question of how much a shipment weighs in total
> > is a question that cannot be asked.
> > Marshall
> Bingo!

However, one /can/ validly ask "please give me the minimum the shipment weighs" and this may still be very useful. This is of course not a defence of null markers (obviously not. its me), but rather just a precaution against ruling out all questions of irregular data in blanket fashion. Our aim should be to provide frameworks that allows us to ask these questions with syntactic correctness /and/ as parsimoniously as possible. Received on Mon Jul 07 2008 - 22:21:20 CEST

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