AlexB

$ cat test.pyfrom sqlalchemy import *metadata = BoundMetaData('sqlite://')metadata.engine.echo = Trueclass Test(object):    passtest_table = Table('test', metadata,        Column('foo', Integer, primary_key=True),        Column('bar', String))m = mapper(Test, test_table, properties = {        'bar': deferred(test_table.c.bar)    })metadata.create_all()session = create_session(bind_to=metadata.engine)t = Test()t.foo = 42session.save(t)session.flush()~$ python test.py[2006-07-11 19:24:55,278] [engine]: PRAGMA table_info(test)[2006-07-11 19:24:55,278] [engine]: {}[2006-07-11 19:24:55,280] [engine]:CREATE TABLE test(        foo INTEGER NOT NULL PRIMARY KEY,        bar TEXT)[2006-07-11 19:24:55,280] [engine]: None[2006-07-11 19:24:55,280] [engine]: COMMIT[2006-07-11 19:24:55,282] [engine]: BEGIN[2006-07-11 19:24:55,283] [engine]: SELECT test.bar AS test_barFROM testWHERE test.foo = ?[2006-07-11 19:24:55,283] [engine]: [42][2006-07-11 19:24:55,284] [engine]: ROLLBACKTraceback (most recent call last):  File "test.py", line 26, in ?    session.flush()  File "sqlalchemy/orm/session.py", line 233, in flush  File "/home/alex/pydev/Sqlalchemy/trunk/sqlalchemy/orm/unitofwork.py", line 231, in flush    trans.rollback()  File "sqlalchemy/orm/session.py", line 55, in rollback  File "sqlalchemy/engine/base.py", line 366, in rollback  File "sqlalchemy/engine/base.py", line 211, in _rollback_impl  File "sqlalchemy/engine/base.py", line 184, in _get_connectionsqlalchemy.exceptions.InvalidRequestError: This Connection is closed