Re: [SQLObject] two beginner's questions

[Luke O. <lu...@me...>]

> What is the goal behind the architecture currently in use vs. the
> kind I
> described?  A lot of my experience in metaclassing comes from
> classic
> classes, so I've learned a lot from the code, but I'm wondering
> what
> particular advantages it has over the late binding I'm describing.
> On
> the surface it appears to be more limiting, but I'm ready to be
> enlightened :)

Hmm, I rather more deeply knowledgable about SQLObject's
implementation than your own, so rather than puzzle it out myself,
care to give a quick overview of the additional things made available
by late binding? If you're not dynamically altering the class based
on sub/super attribs, and you're mapping to a somewhat normalized set
of relations (as opposed to meta-tables of class/attributes or
similar), I don't see the difference from an inheritance perspective
at least. But like I said, you can probably tell me faster than I can
figure it out.

Were there other benefits to the late-binding scheme? I'd say the one
immediate advantage to the metaclass system is that it seems much
easier to introspect on than __getattr__/__setattr__ systems I've
seen in the past.

I suppose of immediate interest to this thread is how a late-binding
system would make implementation-inheritance like the original poster
was looking for possible. It still needs to map to some set of
tables, the easiest but of least interest to me for an ORM being the
meta-table system. (the four primary ways of doing so being mentioned
in the Ambler article I linked to; SQLObject takes the route of
"Table for each concrete class, and all classes are concrete" :) )

- Luke