Re: database design method

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:
>> >
>> > But perhaps one of these days Date will explain to use that this is
>> > what Codd had meant all along. :-)
>>
>> -- Jan Hidders
>
>You mean where Dr. Codd states the following in his "A Relational Model of
>Data for Large Shared Data Banks." paper (p. 380)?
>
>Excerpt below:
>
>"So far , we have discussed examples of relations which are defined on
>simple domains-domains whose elements are atomic (nondecomposable) values.
>Nonatomic values can be discussed within the relational framework. Thus,
>some domains may have relations as elements. These relations may, in turn,
>be defined on nonsimple domains, and so on."
>
>E.F. Codd. "Relational Model of Data for Large Shared Databanks. Comm. ACM
>13, 6 (June 1970)

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