Re: The MySQL/PHP pair

"Dawn M. Wolthuis" <dwolt_at_tincat-group.comREMOVE> wrote in message news:cmg13a$e6k$1_at_news.netins.net...
> "Laconic2" <laconic2_at_comcast.net> wrote in message
> news:CLKdnfG3h-v6mBbcRVn-1w_at_comcast.com...
>>
>> "Dawn M. Wolthuis" <dwolt_at_tincat-group.comREMOVE> wrote in message
>> news:cmem4f$g32$1_at_news.netins.net...
>>
>
> I'm saying that as far as relations go, there is nothing about relations
> that says that using them as a model for data means that you must
> eliminate
> repeating groups (the old version of 1NF). There is no mathematical
> reason
> that a relation must be in 1NF (by the old def).

"A domain is <italics>simple</italics> if all of its values are atomic (nondecomposable by the database management system)."

I don't think this could be any clearer in terms of what Codd said in this particular instance. I've always associated this with the definition of 1NF as the starting point for normal forms, as a natural consequence of the mathematical definition of a relation, but I'll have to admit the linkage is not explicit and might not be self-evident for some, especially if literalism is important. If the repeating groups are logically decomposable, they must be eliminated. If they are not, then they don't have to be. If we assume, which I really don't think we need to do since it seems obvious to me, that a relation is in 1NF by definition, then there is a mathematical reason why a repeating group (your old definition of 1NF) must be eliminated.

Codd also talked about the tendency of people to have trouble with layers of abstraction in some of his papers and how this might lead to misunderstandings about the relational model in contrast to other models. I think that might be the case here.

>
>>
>> > My claim is that there is nothing about modeling data logically as
>> relations
>> > that requires 1NF (as previously defined).

I would say that there is nothing about modeling data logically that requires 1NF. But by definition, a relation is in 1NF. I know we've gone through the paces on this before, but you keep going back. Why not just leave the "Relation" and "First Normal Form" alone and start with something clean, fresh, and new. I think Laconic2 mentioned something like "Dawn' Normal Forms".

>

- Dan Received on Fri Nov 05 2004 - 17:58:47 CET