When I execute this piece of code using a transactional, autoflushing
session against SQLite, I get a ConcurrentModificationError on the
final select:
----------
from sqlalchemy import *
from sqlalchemy.orm import *
eng = create_engine('sqlite://')
sm = sessionmaker(autoflush=True, transactional=True, bind=eng)
session =scoped_session(sm)()
metadata=MetaData()
people_table = Table('people', metadata,
Column('id', Integer, primary_key=True),
Column('name', String(40), nullable=False))
class Person(object): pass
mapper(Person, people_table)
metadata.create_all(bind=eng)
p = Person()
p.name = "Eric"
session.save(p)
p = session.query(Person).filter_by(name="Eric").one()
p.name = "John"
session.rollback()
p = session.query(Person).filter_by(name="Eric").all()
----------
Using a non-transactional session (where the rollback is a no-op), I
have no problem. Turning on SQL echo, I do see something a little
odd--the ORM seems to be holding on to the UPDATE after the rollback.
Interspersing the Python code and the emitted SQL, I see:
----------
p = Person()
p.name = "Eric"
session.save(p)
p = session.query(Person).filter_by(name="Eric").one()
...BEGIN
...INSERT INTO people (name) VALUES (?)
...['Eric']
...SELECT people.id AS people_id, people.name AS people_name
...FROM people
...WHERE people.name = ? ORDER BY people.oid
... LIMIT 2 OFFSET 0
...['Eric']
p.name = "John"
session.rollback()
...ROLLBACK
p = session.query(Person).filter_by(name="Eric").all()
...BEGIN
...UPDATE people SET name=? WHERE people.id = ?
...['John', 1]
...ROLLBACK
Traceback (most recent call last):
[...]
sqlalchemy.exceptions.ConcurrentModificationError: Updated rowcount 0
does not match number of objects updated 1
----------
Is this a bug, or am I misusing the transactional session?
Thanks!
--
Tim Lesher
[EMAIL PROTECTED]
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