# Re: Multiple-Attribute Keys and 1NF

Date: Sat, 01 Sep 2007 12:17:51 GMT

Message-ID: <PLcCi.1809$tB2.1571_at_trndny05>

"Brian Selzer" <brian_at_selzer-software.com> wrote in message
news:Sh3Ci.7571$924.1426_at_newssvr23.news.prodigy.net...

*>
**> "David Cressey" <cressey73_at_verizon.net> wrote in message
*

> news:UfUBi.12075$Eh5.9962_at_trndny06...

*> >
**> > "JOG" <jog_at_cs.nott.ac.uk> wrote in message
**> > news:1188556656.192653.305160_at_r23g2000prd.googlegroups.com...
**> >
**> >> Well I've never suggested multiple values contained in a collection.
**> >> But yes as I said, multiple roles does break the guaranteed access
**> >> rule. My question is now (in the continuuing hunt for the theory
**> >> behind 1NF) is why on earth would that be a problem? I don't see any
**> >> affect on the relational algebra.
**> >
**> > I honestly think that the impetus behind "normalization" in the Codd
*

1970

*> > paper is more of a stopgap than a theory. (I'm not familiar with the
**> > 1969
**> > paper, and I only read the 1970 paper after I began participating in
*

the

*> > discussions in c.d.t.) In the 1970 paper, Codd suggests that it may be
**> > worthwhile to consider the subset of schemas that contain only atomic
**> > attributes. (He didn't use the word "schemas", but I hope I can use it
**> > without introducing confusion.)
**> >
**>
**> The whole point of 1NF boils down to the following two sentences from the
**> June, 1970 article: "The adoption of a relational model of data, as
**> described above, permits the defelopment of a universal data sublanguage
**> based on an applied predicate calculus. A first-order predicate calculus
**> suffices if the collection of relations is in normal form." Therefore,
*

the

*> impetus behind "normalization" is to model the universal data sublanguage
**> after a first-order logic rather than some higher order logic.
*

Thank you, Brian. This clarifies the issue enormously for me. Received on Sat Sep 01 2007 - 14:17:51 CEST