I've been reading up on what Informix and Oracle provide in the way of
object support.
In particular I noticed that in Informix when you SELECT on a table it
by default includes all the objects of sub-classes. In other words the
"*" is postgres terms is always there by default. If you just want that
class only you have to say ONLY(tablename).
To me this is a much better idea. In any proper OO application you would
be using the "*" in postgres 99% of the time - that being the whole
point of OO. Does any consideration want to be given to making the same
change while there's not too many people using the inheritance feature?
I realise breaking compatibility is bad, but I think this is the Right
Thing. When you say "SELECT * FROM animal" it's reasonable that you be
returned all elephants. To not return them is pretty strange for the
uninitiated.
The other thing Informix does is automatically propagate all attributes
including indexes, constraints, pretty much everything to sub-classes.
Again.. I think this is the right thing. Any thoughts?
As for Oracle 8i, as far as I can tell it provides no support for
inheritance whatsoever. The docs themselves say "Oracle doesn't support
inheritance". It's a bit rich really to call it Oracle "object" in any
shape or form.
--
Chris Bitmead
mailto:chris@tech.com.au