python - SQL Alchemy no transaction begun error -

i run following code

db = create_engine('sqlite:///tracking_test.db') db.echo= true metadata = metadata(db) session = create_session(bind=db) #define tables, if exist sqlalchemly find them , sycn otherwise created delivered= table('delivered', metadata,     column('delivered_id',integer,primary_key=true),     column('domain',string(200)),     column('path',string(500)),     )  class delivered(object):             def __init__(self,obj):         self.domain=u'%s' % obj.get("dm","")         self.path=u'%s' % obj.get("pth","")   report1t = table('clicked', metadata,     column('clicked_id',integer,primary_key=true),     column('domain',string(200)),     column('path',string(500)),  )  class report1(object):     def __init__(self,obj):         self.domain=u'%s' % obj.get("dm","")         self.path=u'%s' % obj.get("pth","")   metadata.create_all() mapper(report1, report1t) mapper(delivered,delivered) result= {}#some dict newt = delivered(result) if newt:     session.add(newt)     session.commit()     session.flush() 

and error sqlalchemy.exc.invalidrequesterror: no transaction begun.

the session dict say:

{'autocommit': true, 'autoflush': false, 'transaction': none, 'hash_key': 4317750544, 'expire_on_commit': false, '_new': {<sqlalchemy.orm.state.instancestate object @ 0x101a79ad0>: <__main__.addelivered object @ 0x101a799d0>}, 'bind': engine(sqlite:///adtracking_test.db), '_deleted': {}, '_flushing': false, 'identity_map': {}, 'dispatch': <sqlalchemy.event.sessioneventsdispatch object @ 0x101a82f90>, '_enable_transaction_accounting': true, '_identity_cls': <class 'sqlalchemy.orm.identity.weakinstancedict'>, 'twophase': false, '_session__binds': {}, '_query_cls': <class 'sqlalchemy.orm.query.query'>} 

any 1 know doing wrong?

thanks, cg

it helpful if post full traceback. however, think problem in way create session. think should using sessionmaker rather create_session (i've never seen function before, , don't see documented anywhere). sessionmaker creates new session class, need instantiate. so:

session = sessionmaker(bind=db) session = session() ... session.add(newt)