There are three files:
setup.py
test1.py
test2.py
1. run setup.py to create the sqlite db file
2. run test1.py to create a user and pickle it
3. run test2.py to unpickle the user, check its attributes, and save it to the session
** Make sure test1 and test2 are run in seperate python processes
The assertion in test2.py fails for me. If i take it out, then the save_or_update fails with this error:
sqlalchemy.exceptions.InvalidRequestError: Detected a mapped object not present
in the current thread's Identity Map: '(<class 'setup.User'>, (1,), None)'. Use
objectstore.import_instance() to place deserialized instances or instances from
other threads
On 7/10/06, Michael Carter <[EMAIL PROTECTED]> wrote:
er thats a little weird, when you unpickle the object, have all the
relevant classes had the same Mappers set up on them ? the _state
attribute is a class-level property accessor that will only be there
if the class has been set up with a mapper (as are all the other
properties for which youre looking for default values). the actual
data for _state is in the __dict__ as "_<classname>__sa_attr_state".Yeah, I definitely have the relevant classes set up the same when I pickle and unpickle the object, with the same mapper set up on both.
this is all class-level stuff thats not related to the instance being
in or out of a Session.
I know its class-level stuff, but what it has to do with being in or out of a Session is that you can't put it into the session if it doesn't have a _state attribute.
I will attempt to write a simple test case.
-Michael
import sqlalchemy as sa __all__ = [ 'session', 'User' ]
class User(object): pass
metadata = sa.BoundMetaData('sqlite:///test.db')
users = sa.Table('users', metadata,
sa.Column('id', sa.Integer, primary_key=True),
sa.Column('name', sa.String),
sa.Column('email', sa.String))
users.mapper = sa.mapper(User, users)
session = sa.create_session()
if __name__ == "__main__":
metadata.engine.echo = True
users.create()
try:
import cPickle as pickle
except:
import pickle
from setup import *
u = User()
u.name = 'Michael'
session.save(u)
session.flush()
session.expunge(u)
f = open('pickled_user', 'w')
pickle.dump(u, f)
f.close()
try:
import cPickle as pickle
except:
import pickle
from setup import *
f = open('pickled_user')
u = pickle.load(f)
f.close()
assert hasattr(u, '_state'), "%s has no attribute _state" % u
session.save_or_update(u)
u.email = 'hi'
session.flush()
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