Re: what are keys and surrogates?

On Jan 9, 8:07 am, David BL <davi..._at_iinet.net.au> wrote:
> On Jan 9, 1:25 pm, Marshall <marshall.spi..._at_gmail.com> wrote:
>
> > This issue goes away if we relax 1NF and allow attributes that are
> > lists or relations. This gives us nested structures. (Nested relations
> > are not particularly controversial around here.)
>
> In addition to my previous post, I wish to add another comment
> regarding my suspicion with RVAs. The tuples of a relation are
> supposed to represent facts, but what does it mean when a relation
> merely represents a value?

The question is meaningless. The distinction you are drawing does not exist.

> Isn't the RM meant to have some close
> association with FOPL?

Yes.

> It seems to me there is a fundamental difference between
>
> a) a large collection of propositions relevant to a particular UoD;
> and
>
> b) a composite data structure such as an AST which simply
> "is what it is"

This is an illusion. There is no difference.

Marshall Received on Wed Jan 09 2008 - 17:22:44 CET