Re: a union is always a join!

"paul c" <toledobythesea_at_oohay.ac> wrote in message news:QT9vl.18230$PH1.1832_at_edtnps82...
> Walter Mitty wrote:
>> ...
>>
>> Don't you think Heraclitus said all of this much more clearly, some 2500
>> years ago?
>>
>> http://www.spaceandmotion.com/philosophy-metaphysics-heraclitus.htm
>
>
> Sounds like he was a fine old abstracter (abstractionist?). Seems Abelson
> and company were hip too:
>
> M
>
> (Even while it changes, it stands still.)
>
> Heraclitus
>
> (also):
>
> Plus ça change, plus c'est la même chose.
>
> Alphonse Karr
>
> (both from the esteemed sicp book)
>
> I gather the temporal db people, whatever their arguments, at least agree
> on choosing their desired abstractions up front, not plopping multiple
> interpretations onto the basic Codd model with extraneous lingo like
> 'tense' and 'modal' in today's popular but despicable faux-technocratic
> way. (The general public has allowed the technocrats to usurp their own
> name, just like the once-respectable word 'propaganda' in the 1930's. An
> honest db technocrat ought never venture into metaphysics.).

Do you deny that the set of all domain constraints, relation constraints and database constraints together specify the set of all legal databases? If not then how can you support your statement that 'modal' is extraneous lingo? Correct me if I'm wrong, but didn't Codd use the phrase "time-varying relation" to describe the information carrying structures of the Relational Model? Do you deny that there can be different databases at different times? If not then how can you support your statement that 'tense' is extraneous lingo? You appear to be ignorant of what a modal logic is or what a tense logic is, otherwise you would understand that my usage of the terms is anything but extraneous. I guess that would account for the content of your posts, your inability to recognize that neither the algebra nor the calculus were designed for nor are they sufficient for expressing database updates because database updates cannot be described using just first order predicate logic. There is an implicit tense component to a database update--the notion of before and after...of order, that is alien to first order predicate logic, but not to tense logics. Received on Tue Mar 17 2009 - 00:55:18 CET