Re: Codd's Information Principle

"paul c" <toledobythesea_at_oohay.ac> wrote in message news:2h1Gm.50615$PH1.9648_at_edtnps82...
>I can't remember where in his papers Codd stated the Information Principle
>but here's a version of a quote by Date: "The entire information content of
>a relational database is represented in one and only one way: namely, as
>attribute values within tuples within relations."
>
> Recently there has been mention of logical connectors being implicit in
> tuples, eg. Mr. Scott wrote: "Each row of the join represents a
> conjunction of propositions, one for each operand", ie., what I think is
> called a compound proposition. I sometimes write similar, as well
> regarding disjunctions. But usually my purpose is simply to understand
> the algebra.
>
> I would like to ask where is the "information" to the effect that certain
> rows represent compound propositions recorded?

Where is the "information" to the effect that 2 + 2 = 4 recorded? Certainly not as attribute values within tuples within relations. Received on Fri Oct 30 2009 - 00:38:57 CET