Re: In an RDBMS, what does "Data" mean?

"mAsterdam" <mAsterdam_at_vrijdag.org> wrote in message news:40dd4ca1$0$93324$e4fe514c_at_news.xs4all.nl...
> Anthony W. Youngman wrote:
> > mAsterdam writes
<snip>
>It may be a good exercise to think of MV.FILE as closer
> to SQL.SCHEMA than to SQL.TABLE (and MV.FIELD to SQL.TABLE).
>
> The crucial difference may be in the adherence to the information
> principle. (In some other post you talk about having order
> without specifying it, I think it is similar).
>
> <quote>
> [Information principle] (RM) Date/Codd:
> Chris Date in "EDGAR F. CODD 08/23/1923 – 04/18/2003 A TRIBUTE":
> The entire information content of a relational database
> is represented in one and only one way: namely, as
> attribute values within tuples within relations.
> </quote>
>
> Adherence to it comes with costs and benefits.
> You seem to be convinced that the benefits of non-adherence to it
> easily outweigh the costs (i.e. the benefits of adherence).

Dawn's Information Principle:
The entire information content as well as metadata of a functional database is represented in one and only one way,: namely, as mathematical functions.

Because functions are relations, this is actually tighter. This covers all of the data and the operators -- all can be viewed logically as unctions. --dawn Received on Wed Jun 30 2004 - 03:39:36 CEST