Re: How to normalize this?

On 2013-04-30 22:17:44 +0000, Erwin said:

> It's often bothered me that normalization theory/procedure seems to
> quietly ignore the notion of "nullability or not" of any of the
> attributes in the "initial table design" ...

Nullability doesn't really matter for normalization. From a redundancy point of view null is just another value.

> Iow, that normalization theory per se doesn't actually allow to
> determine when and when not the phenomenon is "an artifact of the
> iniital table design".
>
> Yet iow, that normalization theory doesn't seem to bother whether or
> not the "initial table design" is in fact an accurate relational
> representation of the business problem ...

Keeping the schema equivalent in information content wasn't a goal anyway, and it shouldn't be, otherwise we could not remove certain update anomalies. And I would argue that in practice the different components usually turn out to be independent facts anyway. The fact that they have different underlying dependencies already sort of hints at that. But if you have a realistic example that would show otherwise, that would be interesting.

• Jan Hidders