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Re: atomic

From: David BL <davidbl_at_iinet.net.au>
Date: Wed, 31 Oct 2007 06:07:20 -0700
Message-ID: <1193836040.917858.169670@q5g2000prf.googlegroups.com>


On Oct 31, 4:31 pm, "Roy Hann" <specia..._at_processed.almost.meat> wrote:
> "paul c" <toledobythe..._at_ooyah.ac> wrote in message
>
> news:T6RVi.162603$th2.137089_at_pd7urf3no...
>
> >I know that Codd wrote his first "big" db paper in 1969. At that time I
> >believe the understanding of physical atoms was simpler than it is today
> >but the word "atomic" in most people's minds inherited the physics meaning.
>
> > I wonder if 1NF would seem clearer if it were expressed in terms of
> > "simplest" domains. I suppose there would still be people who would say
> > "but if I look at this way, it's not so simple", eg., when they are
> > talking about some compound key (versus composite key). But the rest of
> > us might not get drawn into the confusions they offer.
>
> It might seem clearer expressed in that way, but it wouldn't express what he
> needed to express. What he needed to express is the idea that none of his
> arguments depend on the internal structure of the values, which they don't,
> shouldn't, and can't.
>
> 1NF does not *require* that values be atomic. It asserts that values will
> be *treated as* atomic. Big difference. Essential difference.
>
> Roy

Can that be formalised? I agree with Bob that in general we have a set of operators and they can allow us to see internal structure. What does it mean for a value to be *treated* as atomic? Received on Wed Oct 31 2007 - 08:07:20 CDT

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