Hello all
I am using Python 2.3 and ZODB (without the rest of Zope) with the
following pattern:
* One process which writes stuff to a ZODB instance (call it test.db)
* Another process which reads stuff from the above ZODB instance
test.db
What I find is that when the first process writes, the second doesn't
pick up the changes. I am sure this must be because I am using ZODB
wrongly, but I can't find any examples that show how to use ZODB in
this way, and I can't find any API docs for FileStorage, Connection,
etc. Reading the source code (from C:\python23\lib\site-packages) has
not thrown up anything useful.
Here's my test code:
A simple database class:
class Database(object):
PersistentObject = persistent.Persistent
PersistentDict = BTrees.OOBTree.OOBTree
def __init__(self, filename, read_only = False):
self.storage = FileStorage.FileStorage(filename, read_only =
read_only)
self.db = DB(self.storage)
self.connection = self.db.open()
self.dbroot = self.connection.root()
Write:
db = Database("test.db")
db.data = db.get_dictionary('data')
sz = len(db.data.keys())
class Datum(Persistent):
def __init__(self, value):
self.value = value
if __name__ == '__main__':
# insert 10 things
for i in range(0, 10):
val = i + sz
d = Datum(val)
db.data[val] = d
transaction.commit()
Read:
db = Database("test.db", read_only = True)
data = db.get_dictionary('data')
If I have a Python shell open and run the above two lines, if I run the
write process repeatedly, the above "data" object never contains any of
the newly added items. To pick them up I have to totally recreate the
"db" object.
I must be doing something wrongly, but I can't figure out what.
Any suggestions?
Thanks,
PC
