ZODB: What does change if classes get persistent?

[Franz GEIGER]

Thank you, Andrew,

that did the trick!

Best regards
Franz


"Andrew Kuchling" <akuchlin at mems-exchange.org> wrote in message
news:3d1yt96vd0.fsf at ute.cnri.reston.va.us...
> "Franz GEIGER" <fgeiger at datec.at> writes:
> > class TCarts(TCollection, Persistence.Persistent):
> >    def __init__(self):
> >       TCollection.__init__(self)
> >
> > TCollection.__init__(self, self)
> > TypeError: unbound method must be called with class instance 1st
argument
> >
> > upon creation.
> >
> > Does anybody know what's going on here behind the scenes?
>
> Ooh, something I forgot to cover.  TCarts is no longer a regular
> Python class, but an ExtensionClass; this breaks the usual convention
> for calling superclass constructors. (Does Python 2.1 try to fix this?
> Anyone from DC know?)
>
> Anyway, the fix would be to use this instead:
>      TCarts.inheritedAttribute('__init__')(self)
>
> See http://www.digicool.com/releases/ExtensionClass/ for a lengthier
> discussion (search for __init__).
>
> > File "C:\Program Files\Python20\ZODB\lock_file.py", line 115, in
lock_file
> > raise error, (StorageSystemError: Could not lock the database file.
> > There must be another process that has opened the file.
>
> Use ZEO if you need to have multiple processes accessing data at the
> same time.  The lowest-level class, the Storage class, isn't written
> to handle concurrent access to the same files.  You probably couldn't
> run two completely different instances of Oracle and point them at the
> same disk partitions, either, and the ZODB's storages impose similar
> limitations.
>
> --amk