Re: Clean Object Class Design -- What is it?

On Wed, 18 Jul 2001, Bob Badour wrote:

> Hi Akmal,
>
> You should warn him that those products that equate object classes with
> relations make a fundamental error. A relation is a set of sets of object
> instances.
>
> Regards,
> Bob

Bob,

I believe this is covered by Chris Date? I remember an article by him in Database Programming & Design quite a few years ago around the time he had published his Third Manifesto. On inheritance he seemed to think that it was a good idea, but couldn't decide about multiple or single.

I've also read stuff by Fabial Pascal. I think in one of his books he covered the issue of OO briefly in an Appendix ("Attack of the Object ..." something or other?)

Unfortunately, I haven't read anything by either gentleman in more recent years. I've tended to become more pragmatic in my outlook having seen some of the problems people face in using databases and OO. on OODBs, it is interesting, but I've had conversations with two groups recently that have been using them and are looking to move to alternatives. The surprise? Well, both wrote chapters for the first OODB book I helped put together :-o

akmal

>
> akmal _at_ city wrote in message ...
> >On 17 Jul 2001, Galen Boyer wrote:
> >
> >> On Mon, 16 Jul 2001, bbadour_at_golden.net wrote:
> >>
> >> >>Object databases take care of
> >> >>inheritance hierarchies internally.
> >> >
> >> > As do relational databases.
> >>
> >> I don't understand how a relational database can represent
> >> inheritance. Most of the time, I can take an object model and
> >> logically map it to a relational model, because of, well, the
> >> relationships, but how do you model inheritance in a DB?
> >> --
> >> Galen Boyer
> >> It seems to me, I remember every single thing I know.
> >>
> >>
> >
> >Inheritance hierarchies have been the subject of some discussion within
> >ANSI/ISO I believe. A number of Object-Relational products support it. You
> >might wish to have a look at something like PostgreSQL:
> >
> >http://www.postgresql.com/
> >http://www.postgresql.org/
> >
> >which is widely available.
> >
> >akmal
> >
> >--
> >[ --- OOPSLA 2001 Workshop on "Objects, <XML> and Databases" --- ]
> >[ http://www.soi.city.ac.uk/~akmal/oopsla01.dir/01-workshop.html ]
> >
> >
>
>
>
>

--
[ --- OOPSLA 2001 Workshop on "Objects, <XML> and Databases" --- ]
[ http://www.soi.city.ac.uk/~akmal/oopsla01.dir/01-workshop.html ]