The attached script fails with this:
Traceback (most recent call last):
File "stale_delete.py", line 33, in <module>
session.flush()
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py",
line 1559, in flush
self._flush(objects)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py",
line 1630, in _flush
flush_context.execute()
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py",
line 331, in execute
rec.execute(self)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py",
line 498, in execute
uow
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/mapper.py", line
2507, in _delete_obj
(table.description, len(del_objects), c.rowcount)
sqlalchemy.orm.exc.StaleDataError: DELETE statement on table 'A' expected to
delete 2 row(s); 1 were matched.in MySQL-InnoDB (works in SQLite and Postgres). Tried versions 0.7.3 and 0.7.5 Python 2.7 I tried manually deleting the rows from the table through MySQL client and noticed that it's not returning an accurate row count (doesn't 'supports_sane_rowcount') for a table with an adjacency relationship and an ondelete='CASCADE'. I'm going to work around this by adding another ondelete='CASCADE' for User->A -- Fayaz Yusuf Khan Cloud developer and architect Dexetra SS, Bangalore, India fayaz.yusuf.khan_AT_gmail_DOT_com fayaz_AT_dexetra_DOT_com +91-9746-830-823
from sqlalchemy import *
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, relationship, backref
Base = declarative_base(bind=create_engine('mysql://root@localhost/test'))
class User(Base):
__tablename__ = 'User'
id = Column(Integer, primary_key=True)
class A(Base):
__tablename__ = 'A'
id = Column(Integer, primary_key=True)
user_id = Column(Integer, ForeignKey(User.id))
user = relationship(User, backref=backref(
'a', cascade='all, delete, delete-orphan'))
parent_id = Column(Integer, ForeignKey('A.id', ondelete='CASCADE'))
Base.metadata.create_all()
session = sessionmaker()()
user = User()
session.add(user)
session.add_all([A(id=1, parent_id=1, user=user),
A(id=2, parent_id=1, user=user)])
session.flush()
session.delete(user)
session.flush()
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