Re: Dawn doesn't like 1NF

From: Dan <guntermann_at_verizon.net>
Date: 15 Oct 2004 19:28:49 -0700
Message-ID: <3e68f717.0410151828.2f7ce474_at_posting.google.com>


"Laconic2" <laconic2_at_comcast.net> wrote in message news:<ye2dnRyBk-N2rO3cRVn-qQ_at_comcast.com>...
> "Dan" <guntermann_at_verizon.net> wrote in message
> news:3e68f717.0410151209.59904d7_at_posting.google.com...
>
> > I don't doubt that introductory textbooks begin with simple examples.
> > Even more than useful or powerful properties, however, one needs a
> > mathematical/logical model that is consistent and complete. I'm
> > simply asking for someone to show me this more powerful and useful
> > model in mathematics that is also as consistent and complete as the
> > "basic" definition of a relation. Sho' me the money.
>
>
> >
> > It shouldn't be that hard to produce an example or "proof" to
> > demonstrate one's assertion, right?
>
> I'll leave that one to the mathematicians.
>
>
> >
> >
> > I've read Date's ideas on this, and I respect them immensely, but I am
> > not entirely convinced that all the fundamental issues have been
> > addressed, such as how calculii and algebra are affected by his model.
>
> You and me both.
>
> I noticed recently that in a discussion of UDT in here, they were
> mentioning some system
> (maybe prolog?) that allows users to define types, but require the user to
> supply the function that test for equality.
>
> There's more here than meets the eye.

Yes!

Testing two of a UDT for equality is
> a whole lot more subtle than comparing the bits, bit by bit. I'm not
> convinced that two values drawn from the same complex domain can be easily
> tested for equality.
>
> Is {1, 2, 3} equal to {2, 3, 1} ?
>
> Is 3.21E3 equal to 32.1E2 ?

Or how about something like: RELVAR BIGGER({set1},{set2})

How does one correlate the implicit binary relational operator with the semantics concerning the internals? We might say set1 is bigger than set2, but how do would a DBMS ensure enforce some semblance of integrity and ensure that this is true in terms of the contents of each set? Much along the same vein as your example, depending on context, bigger could mean many different things (i.e. number of elements, magnitude of an aggregation, etc.).

Regards,

  • Dan
Received on Sat Oct 16 2004 - 04:28:49 CEST

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