Re: Codd's Information Principle
Date: Thu, 29 Oct 2009 23:53:50 GMT
Message-ID: <iWpGm.49811$Db2.27317_at_edtnps83>
Mr. Scott wrote:
> "paul c" <toledobythesea_at_oohay.ac> wrote in message
> news:2h1Gm.50615$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. > >
The values to satisfy that equation might well be recorded in relational form but I presume you are not referring to that, rather to the general truth of the equation as far as conventional arithmetic interpretation is concerned.
I usually try to stay out of the discussions here about truth because a database mechanism is not capable of appreciating that concept the way humans can, just as a database doesn't record persons, only the symbols we use for their names. No offense intended, but I think the question borders on mysticism, imputing human concepts to a db, what Bob B uses the anthrop-word to describe. We are all susceptible to those two attitudes but I think we should make an effort to fall prey to them. Received on Fri Oct 30 2009 - 00:53:50 CET