[Zope3-dev] class lifecycle management/missing attributes

[Garrett Smith]

Peter Simmons wrote:
> Hi,
>=20
> Just out of interest why is an upgrade script like Tres is suggesting?
>=20
> We schedule upgrades so that users aren't using the system, is that
> not possible for your system?
>=20
> I figure there is a good reason but I can't think of it and was
> wondering.=20

I'm not rejecting that option -- just curious as to the alternatives.

In some environments, there is no good opportunity to perform these
upgrades -- 24/7 and all that.

I've use 'lazy' upgrades (automagical, I suppose :-) in other
applications, and they've worked very well. The use, though, was
generally limited to adding new properties. Existing properties were
never deleted or modified, which elimited the cruft that Tres mentioned.

But I'll defer to his wisdom on this one -- I have zero experience with
ZODB, Python persistence, etc.

Is there a facility to quickly track down objects of a particular class
in the ZODB? It would seem invaluable to be able to perform operations
on a set of objects based on class. For obvious reasons, this sort of
thing is taken for granted in RDBs.

 -- Garrett