Re: So let me get this right: (Was: NFNF vs 1NF ...)

"DBMS_Plumber" <paul_geoffrey_brown_at_yahoo.com> wrote in message news:1108073429.138553.182510_at_f14g2000cwb.googlegroups.com...

> Well, I agree with everything you've just said (except for what I think
> your definition of "complex domains" is).

I was being careless in the treatment of "complex domains". Hell, a character string can be complex from the point of view of a character string engine. I think the only relevant issue here is whether the domain can be decomposed by a relational engine. That's what I *think* Codd was dealing with.

I *think* you and I are on the same page about this.

> For 'non-simple' domains where the contents of the domain *can* be
> accessed with project/restrict/join, Codd introduces "normalization".

Agreed.

And I *think* Codd's point was that, by using normalization, a system of relations that requires RVAs can be reduced to a system of relations that is equally expressive and that does NOT require RVAs. And he makes the strong hint that a system that doesn't support RVAs might be easier to implement than one that does support RVAs. I think time has borne that out.

>
> (Confession: I have not read D&D's latest thoughts on RVAs, so I might
> be mis-characterizing their position.)

Confession: Neither have I. Received on Fri Feb 11 2005 - 15:57:44 CET