Re: The Fact of relational algebra (was Re: Clean Object Class Design -- What is it?)

"Ulrich Sprick" <ulrich.sprick_at_gmx.de> skrev i en meddelelse news:3c076e00$1_1_at_news.teuto.net...
> Hi all,
>
> i have just come across this discussion and would like to add my opinion,
if
> you don't mind:
>
> From the programmer's (as i am) point of view an object is an object no
> matter how is represents itself: Wether it is "living" in memory or has
> written it's state into some storage (file, database, ...) for
persistance.
> But i would'nt state that the state written to a storage *is* the object.
if
> another object is created from that record, i expect that new object is in
> exact the same state as the (other) object at the time of writing it's
> state.
>
> greetings,
> ulli

Agreed
Neither memory nor any other storage medium *is* the object - it's just a representation.

A *new* object copied /created may be in the same state, but is not *the same* object

My point to Adrian was that it is *not* wrong (on the contrary: it is right) for
"people (programmers) ... to think (when they work with persitent objects), that the object in the database and the object  in memory is the same".

Whether the physical layout in the DB and the memory differs or not, is just at matter of representation, not of identity. "The same" is in my terminology easured on identity, not representation.

Now this is comp.databases, so I'll leave this OO-matter ...

Regards
Jan

> "Jan Emil Larsen" <jel_at_g-it.dk> schrieb im Newsbeitrag
> news:3c06b6ec$0$25412$edfadb0f_at_dspool01.news.tele.dk...
> > Dear Adrian
> >
> >
> >
> > "Bob Badour" <bbadour_at_golden.net>
> > > > I can only suggest you educate yourself regarding the fundamentals.
My
> > > > previous statement remains a true fact.
> > > >
> >
> > "Adrian Veith" <adrian_at_veith-system.de>
> > > As the uneducated fool I am, I cannot agree to your argumentation.
> >
> > Suggestion:
> >
> > Don't be a fool - educate yourself in the field you want to talk about.
> You
> > need to know more about relational fundamentals!
> >
> > >The confusion arises, because people (programmers) tend to think (when
> they
> > > work with persitent objects), that the object in the database and the
> > object
> > > in
> > > memory is the same. I don't like this idea, because this is not true.
> >
> > Maybe some OO-education as well could be helpfull. An object has state,
> > behavior and identity - that is ONE identity.
> > The object in memory has to be "the same" as the object in the database.
> >
> > Jan Emil Larsen
> >
Received on Fri Nov 30 2001 - 15:06:21 CET