Re: Is relational theory incomplete?

Gödel's proof is of the incompleteness of arithmetic, not relational algebra (or calculus, or...). Essentially, Gödel demonstrated that a theory of arithmetic must contain at least one intensional statement of the form: 'this sentence is false'.

Arithmetic had always been assumed to be purely extensional. Codd's relational theory was purely extensional. Remember all of the early caveats on relational theory of the form 'first order function free'. Those caveats were to insure that the theory was only extensional. To put it in other words, it only dealt with sets of things in the real world. A relational model is a first order description of some subset of the real world.

The cost of this purely extensional restriction is the almost total lack of metadata information available in a relational system.

"mountain man" <hobbit_at_southern_seaweed.com.op> wrote in message news:xJzrb.4373$aT.2467_at_news-server.bigpond.net.au...
> Did Date ever make reference to Godel's
> incompleteness theorem? If so, how did
> he handle it?
>
> How does relational theory come to terms
> with Godel's incompleteness theorem?
>
>
>
>
>
> Farmer Brown
> Falls Creek
> OZ
> www.mountainman.com.au
>
>
>
Received on Mon Nov 10 2003 - 18:32:04 CET