Re: Sets and Lists, again

Gene Wirchenko wrote:
> On 23 May 2006 10:44:59 -0700, "Marshall" <marshall.spight_at_gmail.com>
> wrote:
>
> >Gene Wirchenko wrote:
> >>
> >> In short: The order is logical. The index is physical.
> >
> >The index is derived from the logical order and hence is
> >also logical.
>
> Drivel!
>
> The physical implementation is derived from the logical design
> and hence is also logical? No, it does not work that way.

I think we ought to be able to either agree on this particular point or decide we have different definitions for the same terms. A logical design could be implemented with any number of physical designs. A physical design defines an implementation. So far do we agree?

A list or array could be implemented with tables or linked lists or continuous storage using delimited strings. The list type itself and the names for any values in the list are logical, not physical, right?

I am not at all focused on the physical layer at this point and yet I definitely care about lists because they are a logical structure that you can implement any which way. The list emailAddresses[] is as much a part of a logical data model as a relation EmailAddresses would be. You agree with that, right?

So, what is it about the logical ordering or discussion of the nth element in a list that makes you think we are talking about an implementation? --dawn Received on Tue May 23 2006 - 22:54:52 CEST