tsmiller wrote:
I have a bookstore that uses the ZODB as its storage. It uses qooxdoo as
the client and CherryPy for the server. The server has a 'saveBookById'
routine that works 'most' of the time. However, sometimes the
transaction.commit() does NOT commit the changes and when I restart my
server the changes are lost.
This sounds like you are using mutable data types (like lists or dicts) in
the
non-persistence aware variants.
Christian, thanks for the reply.
When I save a book I save a dictionary where all of the keys are strings and
all of the values are strings. But what you say makes sense. I keep
thinking that it must have something to do with the data itself. I will
check very carefully to make sure that I am not saving anything but strings
in the book record. Thanks. Tom
The problem is not saving things that are not strings, but modifying a
non persistent object without notifying the parent persistent object
that a change has happened and it needs to be saved.
e.g.
you have a persistent object (inherits from persistent.Persistent) pobj
>>> pobj.dict = {}
>>> transaction.commit()
>>> pobj.dict['foo'] = 'bar'
>>> transaction.commit()
>>> print pobj.dict
{'foo': 'bar'}
#restart your python process
>>> print pobj.dict
{}
Instead you must either tell zodb the object has changed:
>>> pobj.dict = {}
>>> transaction.commit()
>>> pobj.dict['foo'] = 'bar'
>>> pbj._p_changed = True # alternatively: pobj.dict = pobj.dict
>>> transaction.commit()
>>> print pobj.dict
{'foo': 'bar'}
#restart your python process
>>> print pobj.dict
{'foo': 'bar'}
Or use a persistence aware replacement.
>>> from persistent.mapping import PersistentMapping
>>> pobj.dict = PersistentMapping()
>>> transaction.commit()
>>> pobj.dict['foo'] = 'bar'
>>> transaction.commit()
>>> print pobj.dict
{'foo': 'bar'}
#restart your python process
>>> print pobj.dict
{'foo': 'bar'}
The same principles apply to other mutable non-peristent objects, such
as lists.
Laurence
_______________________________________________
For more information about ZODB, see the ZODB Wiki:
http://www.zope.org/Wikis/ZODB/
ZODB-Dev mailing list - ZODB-Dev@zope.org
http://mail.zope.org/mailman/listinfo/zodb-dev
