Re: Demo: Modelling Cost of Travel Paths Between Towns

From: Neo <neo55592_at_hotmail.com>
Date: 17 Nov 2004 18:51:18 -0800
Message-ID: <4b45d3ad.0411171851.6046d3b@posting.google.com>

> > The query should not mention NULL anywhere. Why?
> > Because you db shouldn't have NULLs to begin with.
>
> I did that already: WHERE age > 0, etc, though I personally have no problem
> with NULLs, nor have they ever given me a data problem.

I assume you are referring to "use the value 0 to indicate unknown age." from your other post. If two things have age 0, is it true or false that their ages are equal?

Do you have any idea why CJ Date would state in his book "NULLs and 3VL undermine the entire foundation of the relational model"? Received on Wed Nov 17 2004 - 20:51:18 CST