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

On Sun, 6 Feb 2005 07:35:09 -0000, "Roy Hann" <specially_at_processed.almost.meat> wrote:

>> > 1NF means (and has always meant) that all values are
>> >atomic (simple, indivisible)
>>
>> Atomic is not a precise word. We can not base any precise definition
>> on that term.
>
>Alan is confused, but your comment, erudite though it is, is irrelevant.

I have to disagree, because my coment was intended to clarify Alan's confused post.

I can accept that my comment was not very precise, but not that is was irrelevant.

>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.

Agreed.

> The theory therefore does not need to
>define what atomic means.

But it needs to use precise terms, and atomic is not.

The proof is that the overwhelming part of the people (professors included) think that 1NF means: "values are simple and indivisible"

> 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."

But it was a very unfortunate term election that is causing a lot of confusion even 35 years later.

> I can't think of any
>other theory where a precise definition is demanded for things that are
>*intended* not to be discussed.

But the formulation of a theory must be precise, and it must not lead to massive misconceptions which have important implications in what is discussed.

>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.

Agreed

Regards Received on Sun Feb 06 2005 - 16:36:49 CET