RE: [Pythoncard-users] ZODB Persistence

Not entirely true. With ZODB there is a standard method (can't remember the
name) called on each object as it is retrieved from storage. So if the class
has changed you build into that standard method the code required to deal
with the change (add default values to new properties, etc.). Or you write a
batch program that touches every single instance of the changed class and
update existing values as necessary.

Not necessarily ideal, but at least there are mechanisms.

---
Patrick K. O'Brien
Orbtech

> -----Original Message-----
> Kevin Altis wrote:
>

[snip]

> 7. One of my biggest concerns with ZODB as our general mechanism is also
> valid for Shelve, but Shelve would be easier to deal with.
> Namely, there are
> no good ways of dealing with data stuffed into an object database when you
> go and change the classes. Perhaps versioning and careful attention to
> backward compatible class changes will help, but this is a pretty
> fundamental issue.
>
> People interested in ZODB should join or at least follow the ZODB-dev list
> http://aspn.activestate.com/ASPN/Mail/Browse/Threaded/ZODB-dev
>
> ka
>
>
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