SQLAlchemy: ValueError

Question

我有以下表: 1)用户

class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key = True)
    fname = Column(String(45))
    lname = Column(String(45))
    mail = Column(String(45))
    password = Column(String(45))

    courses = relationship("Course", secondary=user_course, backref="users")
    universities = relationship("University", secondary=user_university, backref="users")

    def add_university(self, university):
        universities = self.universities
        universities.append(university)
        self.universities = universities

    def add_course(self, course):
        courses = self.courses
        courses.append(course)
        self.courses = courses

2)大学

class University(Base):
    __tablename__ = 'universities'
    id = Column(Integer, primary_key=True)
    date = Column(DateTime)
    name = Column(String(45))

3)课程

class Course(Event):
    __tablename__ = 'courses'
    id = Column(Integer, ForeignKey('events.id'), primary_key=True)
    name = Column(String(45))
    year = Column(Integer)

    __mapper_args__ = {
        'polymorphic_identity':'course',
    }

    events = relationship("Event", secondary=course_event, backref="courses")

所以，很多人对很多人都有用户课程和用户大学，很多人对很多人有课程事件(当然是家长)。

当我试图用用户定义的方法添加一所大学时，它是有效的，但是当我试图添加一个课程时，我会得到以下错误：

回溯(最近一次调用)：

 File "/Users/arnoutaertgeerts/Documents/Eclips/SlideTalk 2.0/test_SQL.py", line 473, in <module>
    arnout.add_course(Analyse)
  File "/Users/arnoutaertgeerts/Documents/Eclips/SlideTalk 2.0/test_SQL.py", line 101, in add_course
    courses.append(course)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 1046, in append
    item = __set(self, item, _sa_initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 1021, in __set
    item = getattr(executor, 'fire_append_event')(item, _sa_initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 714, in fire_append_event
    item, initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/attributes.py", line 800, in fire_append_event
    value = fn(state, value, initiator or self)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/attributes.py", line 1026, in emit_backref_from_collection_append_event
    passive=PASSIVE_NO_FETCH)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/attributes.py", line 854, in append
    collection.append_with_event(value, initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 655, in append_with_event
    getattr(self._data(), '_sa_appender')(item, _sa_initiator=initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 1046, in append
    item = __set(self, item, _sa_initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 1021, in __set
    item = getattr(executor, 'fire_append_event')(item, _sa_initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/collections.py", line 714, in fire_append_event
    item, initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/attributes.py", line 800, in fire_append_event
    value = fn(state, value, initiator or self)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/attributes.py", line 1020, in emit_backref_from_collection_append_event
    _acceptable_key_err(state, initiator)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/SQLAlchemy-0.7.9-py2.7.egg/sqlalchemy/orm/attributes.py", line 982, in _acceptable_key_err
    manager_of_class(initiator.class_)[initiator.key]))

ValueError:与User.courses类型的属性无关的对象

然而，如果我停止让课程继承事件，它确实有效！

有什么想法吗？

Answer 1

问题解决了！这是票：http://sqlalchemy.org/trac/ticket/2674