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

From: Jim Melton <Jim.Melton_at_Technologist.com>
Date: Sat, 01 Sep 2001 23:13:21 GMT
Message-ID: <3B916B92.57A9F061@Technologist.com>

Bob Badour wrote:

> >> I understand that ODBMSes require one to program in order to enforce
> >> integrity because they generally treat integrity enforcement as nothing
> more
> >> than a sub-task in every other task (or method, if you prefer).
> >
> >Well, it depends. If you mean referential integrity, your statement is not
> >universally true. If, on the other hand, you mean constraints such as "a
> >location is expressed as a latitude/longitude pair in decimal degrees where
> >east/north are positive" then yes, ODBMS require programming. And so, I
> submit,
> >would any other database.
>
> Nope. Such a declaration is still just a declaration. Where does one define
> pre- and post-conditions? What are pre- and post-conditions? What about
> other invariants and assertions? OO proponents have widely stipulated in
> this thread and other recent threads that constraints are baked into methods
> such as insert and delete.

Then we are debating language capabilities and not paradigms. I program in C++. C++ does not have any way to declare pre/post conditions (and automatically generate the requisite code to enforce them). Other languages do.

Which leads me to think that while it may be possible to declare pre/post conditions and allowable values and other integrity constraints, unless those declarations are "executed" to enforce the constraint they are just so much window dressing. So I guess I'll stick with my (albeit wrong in your opinion) definition that such statements are indeed programming.

--
Jim Melton, novice guru             | So far as we know, our
e-mail: Jim.Melton_at_Technologist.com | computer has never had
v-mail: (303) 971-3846              | an undetected error.


Received on Sat Sep 01 2001 - 18:13:21 CDT

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