Re: Few confusing things about first normal form

On Oct 23, 9:11 pm, paul c <toledobythe..._at_oohay.ac> wrote:
> David BL wrote:
>
> ...
>
> > Is the value of an attribute that is an RVA a scalar?
>
> I believe it is ie., in a "containing" tuple it's a (single) relation
> value and (in the D&D approach) there is no way to operate on its
> individual tuples. Their algebra only operates on the value of the
> relation.
>
> (They have an operator called UNGROUP that forms a different relation
> that has no RVA's. Definition in thethirdmanifesto.com, see appendix A.
> They don't the equality operator to treat the second relation as equal
> to the first even though some of the possible values for the containing
> /GROUPed relation might have exactly the same information as the
> UNGROUPed one. However, I don't believe they forbid an operator apart
> from equality that decides some kind of equivalence.)
>
> Hope somebody will correct me if I've mangled what D&D say.

Isn't every type a scalar type? Why not drop the word "scalar" as meaningless? In fact it would seem a good idea to avoid the confusion with the rather specific meaning of "scalar" used in linear algebra (where it is associated with the field over which matrices and vectors are defined). Received on Fri Oct 24 2008 - 05:27:51 CEST