Re: OO and relation "impedance mismatch"

"Bernard Peek" <bap_at_shrdlu.com> wrote in message news:s$KWpET71WcBFwY5_at_shrdlu.com...
> >
> >The few formal descriptions of object oriented modeling I've seen say that
> >the "class" is an OPTIONAL construct in object oriented modeling, while
> >the "object" is fundamental. Maybe I'm missing something. Can you clarify?
>
> That's why I think the impedance mismatch is within the OO community.
> The languages that OO programmers use seem to insist on classes, so
> people keep trying to implement them in OO databases. I'd be interested
> to see what would happen if a COBOL programmer designed an OO database.

Unless the COBOL programmer is up to speed on inheritance, polymorphism, and encapsulation, it's not going to be very OO, even if it ends up being a good database. My sense is that COBOL isn't big on these features, although I know little about COBOL.

The impedance mismatch has everything to do with the difference between values and variables, and nothing to do with class-row vs. class-attribute, Date's First Great Blunder notwithstanding. It also has to do with the logical-physical separation, and with declarative vs. procedural, and physical addressing vs. content-based addressing. None of these problems particularly exclude an OO approach, although the values vs. variables one is a bit tricky to get right.

Marshall Received on Sun Oct 17 2004 - 01:28:26 CEST