Re: [T] Clean Object Class Design -- What is it?

> ....
> I guess what's troublesome to me is that we have to build some
> complex/awkward constructs in an RDBMS to represent something that is quite
> natural in the object-oriented realm.

Do you mean inheritance? See below.

> However, I'm not an OODBMS zealot.
> An RDBMS is the superior choice for systems where diverse applications will
> be accessing a central data store.

I fully agree with that point :-)

> I tend to like OODBMSs for
> application-specific data stores (embedded apps in particular).
>
> >
> > As far as modeling, I agree with the prior message that
> > you have not established a sufficient basis for
> > "subtyping" here. Those "types" you gave could change,
> > merge, etc. (I can envision commercials for a
> > half sportscar and half SUV, or new gov laws WRT
> > classifications.) One should only subtype if the divisions
> > are permanent and significant. (I rarely find those
> > for commerical and biz apps, BTW.)
> >
>
> This is why I made the next example completely abstract. The point wasn't
> to have a toy example picked apart, but instead to illustrate the problem of
> representing inheritance using an RDBMS.

You are right in that RDBMS are poor at inheritance (in their current form).

However, for my domain I rarely find a decent use for inheritance. This is why we often get into the "OO is also good at non-tree stuff" fights here.

If your domain can effectively use inheritance, then translating from a RDBMS to OO is something that I
don't have much advice/experience
to give you. I also suspect that the best translation/conversion technique is situation-specific. Thus, you may not be able to get a decent answer without presenting the actual usage I am afraid.

BTW, what is your primary domain (industry)?

> I guess I should have stated that
> more clearly when I presented the initial problem. Typical issues with
> communicating via Usenet I suppose. :-)
>

-T- Received on Sun Jul 22 2001 - 01:34:43 CEST