Re: NULLs: theoretical problems?

On 11 Aug, 12:20, Jan Hidders <hidd..._at_gmail.com> wrote:
>
> Heck, I could even explain it in Dutch for you. ;-)
>
> But also then it wouldn't make sense. Any argumentation that is based
> on taking the definitions in standard normalization theory and
> applying them to relations with null values is based on a fallacy. If
> you really want a meaningful discussion you first need to come up with
> a proper formal definition of a relation with null values, update
> anomalies, redundancy, dependencies, et cetera. That, by the way, is
> actually not as hard as you might expect, but it still needs to be
> done.
>
> -- Jan Hidders

Jan, I agree with you. I don't know of any such formal definition that deals with nulls. What I was trying (and probably failing) to do was to show that by the present definitions we cannot find nulls to be acceptable in dependencies or in normalized relations. I was trying to do so without commenting on whether nulls can be permitted in relations at all (but naturally I agree that they can't).

--
David Portas