Re: Looking for how to model 3D objects in 2D relational databases

Gene Wirchenko wrote:
> On 9 Oct 2005 09:01:56 -0700, "Marshall Spight"
> <marshall.spight_at_gmail.com> wrote:
>
> [snip]
>
> >The first thing you need to observe is that relational databases
> >are not 2D. A dimension is a measure independent of any other
> >dimensions. The columns of a relational table are independente;
> >they are dimensions.
>
> That has bothered me for some time now.
>
> Given a PK, the columns are not independent. By that, the
> dimensionality of a table would be the number of columns in the key.
> What am I missing?

Exactly. This is why some tables are even called dimensions in DW terminology. For example, it would be ridiculos to suggest that

Time(year, month, date)

is a 3 dimensional entity. On the other hand, we have fact tables, which could clearly have any number of dimensions. Received on Mon Oct 10 2005 - 23:10:37 CEST