Re: History of 1NF

From: David Cressey <>
Date: Thu, 13 Mar 2008 13:43:36 GMT
Message-ID: <ccaCj.5896$FG2.4830_at_trndny08>

"JOG" <> wrote in message
> On Mar 12, 5:19 pm, Marshall <> wrote:
> > Back in the day, Codd originally defined First Normal Form
> > (or maybe he was just calling it Normal Form back then)
> > and proved something about it. Something about an
> > isomorphism between nested relations and unnested
> > relations? Could someone state specifically what he
> > proved, please? And if anyone has a reference, that'd
> > be good too.
> >
> > Thanks,
> >
> > Marshall
> I'm afraid I don't have links for you, but I doubt that anything was
> strictly proven - Codd's initial publications were example driven (and
> rightly so, given he was attempting to lead people out of a status quo
> at the time). But also, has it not been shown that some boundary cases
> do require nested relations to model? (but I'd need to hit the acm
> portal to check that).
> My intuition is (as in its a complete guess) that Codd, as a
> mathematician, started with the notion of using relational theory, and
> aware of the previous work on "conjunctive" and "disjunctive normal
> forms", harnessed their conceptual basis and terminology to apply to
> propositions. The clever sausage. Regards, J.

In the paper, or maybe the footnotes, Codd makes reference to prior use of the relational data model. The prior use he refers to are knowledge engines or inference engines, I forget the terminology. What Codd was introducing in the 1970 paper was the use of the relational data model for the architecture of database management systems. Codd may have coined the term "data model". But the idea, with or without that label, had been bouncing around computational circles for five years or more.

It's common for all of us to say that Codd "invented the relational data model". And, as far as database work goes, that is by and large true. At the time of the 1970 paper, the database task group (DBTG?) had just submitted its report, and the CODASYL data model was about to take the database world by storm. And, if anybody had had to choose the "foremost thinker in database concepts", it probably would have been Charles Bachman. Charles Bachman and
Ted Codd had the "great debate" about graph data models versus the relational model sometime in the 1970s.

Without a doubt, Codd's ideas made it much easier to compare two data systems, point for point, on a systematic basis, rather than just saying "I like it, so it must be good". Received on Thu Mar 13 2008 - 14:43:36 CET

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