Re: 1 NF

From: Cimode <>
Date: 1 Mar 2007 07:20:43 -0800
Message-ID: <>

On Mar 1, 3:32 pm, "Anith Sen" <> wrote:
> "-CELKO-" <> wrote in message
> >>> the relation that contains the combinations of parts ever shipped in one
> >>> or more shipments, a set of sets if you will. <<
> > This is not 1NF in most cases be a single attribute because each part
> > has meaning in the data model. YOu teally do want to look at them. To
> > make 1NF atomic you would need a data model in which the lowst unit is
> > the shipment -- a container level model.
> >>> If it is a single attribute relation, then it may be hard to display
> >>> without some device such as a "generated key". <<
> > You would usually have a shipment number that might be derived from
> > source, destination, etc.
> >>> If certain relations we can imagine are not possible in Codd's RM
> >>> without an arbitrary number of attributes then I'd think that his theory
> >>> is broken. <<
> > The theory is still good; modeling is hard.
> > And not everything fits into RM. Documents and text searching require
> > semantics and return a fuzzy revelance match number. Pictures are
> > even worse. A human can look at a political cartoon, a symbol
> > (Doonsberry's floating war helment) and a photogrpah and know that
> > they are all George Buch. There is no way to write a join for that
> > kind of matching.
> "It has emerged from a study of the use of language in argument and
> persuasion and it is based on the identification and examination of those
> parts of language, which are essential for these purposes. It is formal in
> the sense that it lacks reference to meaning. Thereby, it achieves
> versatility: it may be used to judge the correctness of a chain of reasoning
> (in particular, a "mathematical proof") solely on the basis of the form (and
> not the content) of the sequence of statements which make up the chain."
> " The use of anthropomorphic terminology when dealing with computing systems
> is a symptom of professional immaturity."
> " matter how desirable it is for computerized systems to fully
> understand user meaning (the interpretation expressed by external
> predicates), unless those predicates can be directly formalized, internal
> predicates-and thus, predicate logic/the relational model--are the best we
> can currently do to guarantee consistent mechanized inferences."
> --
> Anith
> > Fractals curves also have problems, since there is
> > an infinite distance between any two points and you cannot determine
> > if a point is inaide or outside of a closed fractal curve.

Thanks...I would not have said it better.. Received on Thu Mar 01 2007 - 16:20:43 CET

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