Re: Date's First Great Blunder

"Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message news:c5jivl$8ca$1_at_news.netins.net...
> > "Dawn M. Wolthuis" <dwolt_at_tincat-group.com> wrote in message
> news:<c5ia56$t04$1_at_news.netins.net>...
> OO, like relational database theory, does have religious followers, but
I'm
> guessing that most practitioners of each are more pragmatic than dogmatic,
> working to develop and maintain information systems. It "works" to
specify
> a "record" by way of an OO class and include persistence methods in the
> class

No, it doesn't. I don't know a single competent OO programmer who does that. At most, I'd generate such with XDoclet or another tool. Such techniques scale very poorly, especially when you have object graphs - does only the parent get "persistence methods", or the children too? There are many more flaws with this, but suffice it to say that no OO programmer (other than a beginner) would handle "persistence" this way.

> -- and that is what's "evident" to "the vast majority of the OO
> coders", I suspect.

Not a single one that I know.

> > A class is a type and "object" is the mix and confusion of the
> > "variable" and "value" concepts.
>
> Is a class a type or a definition of a type? A type, being a domain, is a
> set.

That set also has a specification. And a type has operators too.

> A class is a specification where the set of all objects that can be
> instantiated using that specification constitute the domain (or the set
that
> actually ARE instantiated, depending on your definition of domain).

So a domain is only those objects that already exist? That makes little sense. How does a type differ from its specification? See "set intension" vs "set extension."

> > Metadata is data like any other data, and it should be represented in
> > the form of relations.
>
> Or in the same for as other data, agreed. Code is metadata..

About what? What data does it concern? Another flaw in OO is its (usual) requirement that every bit of code be tied to one class, regardless of how many classes it concerns.

• erk