Re: database design method

"Jan Hidders" <hidders_at_REMOVE.THIS.uia.ua.ac.be> wrote in message news:3dd03675$1_at_news.uia.ac.be...
> D Guntermann wrote:
> >
> >"Jan Hidders" <hidders_at_REMOVE.THIS.uia.ua.ac.be> wrote in message
> >news:3dd011dd$1_at_news.uia.ac.be...
> >> D Guntermann wrote:
>
> Where does Codd speak here about abstract identifiers? Or do you mean that
> Codd already here suggested nested relations? That is certainly
> true, but he then proceeds with explaining in section 1.4 how these should
> be normalized away.
>
> -- Jan Hidders
>
>
So he does.

Just prior to 1.4, he discusses confusion due to failure to distinguish between type and instance with a very direct reference to "record". I gather that he considers a relation value in a relation tuple to be of a _complex domain_ because he considers them to be repeating/multiple instances of tuple types rather than one encapsulated instance of a relation type.

His naming of attribute roles as _jobhistory_, _salaryhistory_, and _children_ in Figure 3(a) almost seemed like abstract identifiers at one point. Could there be such a thing as "conceptual encapsulation"?

Regards,

Daniel Guntermann Received on Tue Nov 12 2002 - 02:23:03 CET