Re: Can we solve this -- NFNF and non-1NF at Loggerheads

From: Paul <paul_at_test.com>
Date: Mon, 07 Feb 2005 13:35:04 +0000
Message-ID: <42076e88$0$42537$ed2619ec_at_ptn-nntp-reader03.plus.net>


Roy Hann wrote:
> 1NF does not "mean values are simple or indivisible". It just says that for
> the purpose of the relational theory, the divisibility (or internal
> structure) of values of a given type is of no interest or use within the
> theory. The theory does not make use nor reference to the internal
> structure of a value of any type. The theory therefore does not need to
> define what atomic means. The term "atomic" is a just a narrative
> short-hand that Codd used to say, "That's stuff I don't care about, so
> forget about it from now on as you read this paper." I can't think of any
> other theory where a precise definition is demanded for things that are
> *intended* not to be discussed. Plane geometry isn't required to define
> colour for the purpose of excluding it from discussion.
>
> There is nothing in RT that *prevents* values from being divisible, there
> never was, and it would plainly be stupid to want it that way.

This sounds to me like an excellent summary of what "1NF" and "atomic" means. I can't believe we go round in circles discussing this point when it really is this simple!

Paul. Received on Mon Feb 07 2005 - 14:35:04 CET

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