Re: Sets and Lists, again

Gene Wirchenko wrote:
> On 22 May 2006 17:49:21 -0700, "dawn" <dawnwolthuis_at_gmail.com> wrote:
>
> >Gene Wirchenko wrote:
> >> On 22 May 2006 16:42:22 -0700, "dawn" <dawnwolthuis_at_gmail.com> wrote:
> >>
> >> [snip]
> >>
> >> >I'm working at the logical level where an index holds the ordinal
> >> >position. This position can be selected just as any attribute (derived
> >> >or otherwise). There is no renumbering required.
> >>
> >> Indexes are physical, not logical.
> >
> >No. I am using the term as an index of an array. Array[n] where n is
> >the index. If there is a list in a DBMS named emailAddresses, then the
> >3rd element of that array is (logically) emailAddresses[2] (or [3],
> >depending on the implementation of Arrays) and '2' (or '3') is the
> >value of the index for that element.
>
> Since you are discussing implementation, it is physical.

I brought in implementation for clarification of the term. Surely one can have logical arrays, just as one can have logical scalars, logical relations, logical functions, etc. Index values come from a set, just as the domain of any function does. Where does the physical part enter into this? --dawn Received on Tue May 23 2006 - 19:25:51 CEST