Dear Rich (01)
>
> > I have always considered the definition of an RDB-class
> correspondence to be
> > partially in the mind of the modeler, not in the RDB structure
> itself. I
> > know of no formal definition of what a RDB-class consists of, which
> would
> > provide a rigorous foundation for translating RDBs to classes with
> one
> > exception; there is at least one class per table. Modelers may often
> add
> > definitions of subclasses within a table, but that's usually some
> form of
> > correspondence between groups of columns from a table that fit within
> the
> > human "chunk" size of 7+/-2 concepts. So it seems every bit as
> subjective
> > as any other method of constructing classes from data. Data mining
> (and
> > text mining) consists of discovering those subclasses, along with
> classes
> > that relate one table to other(s).
>
> I would not dispute any of this.
>
> > Do you have reference(s) (URLs especially) to other documented points
> of
> > view which might more rigorously define how the RDB translates into
> classes? (02)
[MW] I did some work that effectively does this about 15 years ago, which is
captured in a document called "Developing high Quality Data Models". Part of
it is about finding the hidden classes, and part of it is about not hiding
them in the first place. You can find it here:
http://www.matthew-west.org.uk/Publications.html (03)
or just type "High Quality Data Models" into Google. (04)
Regards (05)
Matthew West
Information Junction
Tel: +44 560 302 3685
Mobile: +44 750 3385279
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.matthew-west.org.uk/ (06)
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