Re: Views for denomalizing

"Alfredo Novoa" <alfredo_novoa_at_hotmail.com> wrote in message news:u2da01tjpr0sljmjajsrgdih80gtcpp78a_at_4ax.com...
> 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.
><snip>
>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.

Does the other topic I started on this on how products that now describe one of their features as being that they are Non-First-Normal-Form (NF2 or NFNF, for example) are now, be definition, potentially IN 1NF by the new definition. So, NFNF is no longer in non-1NF by the new definition of 1NF. This is what happens when you redefine a term. These terms are, in some sense, the "API" for relational theory -- you can change your implementation, but not your API without significant problems. You can see that Alan didn't get the memo when a significant term in the theory just got redefined by some of the core players in relational theory. I'm guessing he would have heard if the word were spread that we no longer needed to model data in 1NF (of course we have never needed to, but relational theorists are just coming back to that position now).

>> 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.

That is great, but hiding that fact by simply redefining underlying terms is confusing the message. People can now say some of the same words and mean something entirely different and their audience might not even know.

>> 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.

Perhaps you will trust me that there are such tools where "null" is the name of a value which can be compared using a two-valued logic. The use of two-valued logic is more in line with many theorists, although some would prefer to head toward more, rather than fewer, truth 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.

Correction: Nothing with a SQL null or a three-valued logic null can be a relation, but for tools where "null" is a value, this is not an issue.

>>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.

Wasn't Codd an IBM employee when he wrote his early papers? I'm thinking there are people at IBM who know quite a bit about relational theory, whether they opt to completely buy into it or not.

>>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?

Just in case it wasn't really clear where the problem was in this thread, I started the other thread about that. Did that help clarify where the issue is? --dawn

>
> Regards
>
Received on Sun Feb 06 2005 - 01:24:22 CET