Re: Views for denomalizing

On Fri, 4 Feb 2005 10:32:01 -0600, "Dawn M. Wolthuis" <dwolt_at_tincat-group.comREMOVE> wrote:

>I'm interested in getting the word out on how what-use-to-be-called-1NF is
>now NOT NECESSARY -- AT ALL!

Indeed, it is not necessary.

> By folks like Date and you simply changing
>the meaning of 1NF, no announcement is going out to professors in any big
>way that the ought not teach 1NF like they used to, nor to data model
>practitioners that they don't have to remove those relation-valued
>attributes when modeling for any reason than tools not supporting their
>efforts, etc

This is not the only mistake spreaded by professors.

>I want to spread the word -- what used to be referred to as 1NF, that I now
>have to find some other term for because otherwise I keep calling it 1NF, is
>DEAD!
I don't see a lot of usefulness in creating such a term.

> I don't find it helpful at all that the term has been redefined.

I don't understand you. The redefinition of the term means that the old 1NF that you disliked so much is dead. The old 1NF constraint was removed and this is sometimes helpful.

> I
>can see that helps with the slight of hand that is being done in relational
>circles. How can we get the word out that 1NF, as understood in the 70's,
>80's and by many sense that time, is no longer?

That is very difficult because few people is interested in being well informed.

>>>and relations, by definition do NOT have duplicate tuples (or rows, in
>>>SQL-speak).
>>
>> Nor nulls.
>
>This always throws me off since it is SQL NULLS -- three-valued logic
>NULLs -- that are disallowed. For any tools where NULL is a value, rather
>than the absense of value, this is not an issue.

I don't know such tools. SQL nulls are not values.

> I think I am correct in
>saying that there is no such rule required when working in a two-valued
>logic rule (which is where I prefer to work).

But there is a rule that says that all the tuple attributes must have a value, so nothing with nulls might be a relation.

>However, the model defines itself (and IBM defines
>it) as being a NF^2 (NF squared) or Non-First Normal Form database.

IBM knows very little about the Relational Model. You should ignore all that.

>So, you
>can see how this redefinition of 1NF, while it works for Date and for you,
>is terribly confusing to some of us.

Where is the problem?

Regards Received on Sat Feb 05 2005 - 22:03:42 CET