SQLAlchemy的---「對象類型「ROLE_USER」有沒有屬性「foreign_keys」

Question

class User(Base): 
    """ 
     users table 
    """ 
    __tablename__ = 'users' 

    __table_args__ = { 
     'mysql_engine': 'InnoDB', 
     'mysql_charset': 'utf8' 
    } 

    id = Column(INTEGER, primary_key=True) 
    email = Column(String(64), nullable=False, unique=True) 
    password = Column(String(64), nullable=False) 
    name = Column(String(32), nullable=False) 
    last_login_time = Column(DateTime, default='') 
    last_login_ip = Column(String(32), default='') 
    create_time = Column(DateTime, nullable=False) 
    status = Column(SMALLINT, default=0) 
    role = relationship("Role", 
        secondary="role_user", 
        backref=backref('user')) 

    def __init__(self, email, password, name, last_login_time=now, 
          last_login_ip='0', create_time=now, status=0): 
     self.email = email 
     self.password = md5(password) 
     self.name = name 
     self.last_login_time = last_login_time 
     self.last_login_ip = last_login_ip 
     self.create_time = create_time 
     self.status = status 

    def __repr__(self): 
     return "<User('%s', '%s')>" % (self.name, self.email) 

class Role(Base): 
    """ 
     roles table 
    """ 
    __tablename__ = 'roles' 

    __table_args__ = { 
     'mysql_engine': 'InnoDB', 
     'mysql_charset': 'utf8' 
    } 

    id = Column(SMALLINT(5), primary_key=True) 
    name = Column(String(32), nullable=False, unique=True) 

    def __init__(self, name): 
     self.name = name 

    def __repr__(self): 
     return "<Role('%s', '%s')>" % (self.id, self.name) 


class role_user(Base): 
    """ 
     role_user association table 
    """ 

    __tablename__ = 'role_user' 

    __table_args__ = { 
     'mysql_engine': 'InnoDB', 
     'mysql_charset': 'utf8' 
    } 

    user_id = Column(INTEGER, ForeignKey('users.id'), primary_key=True) 
    role_id = Column(SMALLINT(5), ForeignKey('roles.id'), primary_key=True) 

    def __init__(self, user_id, role_id): 
     self.user_id = user_id 
     self.role_id = role_id 

當我創建一個用戶，我遇到了錯誤：

u1 = User(email='john@example.com', password='12345', name='john') 
Traceback (most recent call last): 
    File "<console>", line 1, in <module> 
    File "<string>", line 2, in __init__ 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/instrumentation.py", line 310, in _new_state_if_none 
    state = self._state_constructor(instance, self) 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/util/langhelpers.py", line 582, in __get__ 
    obj.__dict__[self.__name__] = result = self.fget(obj) 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/instrumentation.py", line 145, in _state_constructor 
    self.dispatch.first_init(self, self.class_) 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/event.py", line 409, in __call__ 
    fn(*args, **kw) 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/mapper.py", line 2209, in _event_on_first_init 
    configure_mappers() 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/mapper.py", line 2118, in configure_mappers 
    mapper._post_configure_properties() 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/mapper.py", line 1242, in _post_configure_properties 
    prop.init() 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/interfaces.py", line 231, in init 
    self.do_init() 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/properties.py", line 1028, in do_init 
    self._setup_join_conditions() 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/properties.py", line 1102, in _setup_join_conditions 
    can_be_synced_fn=self._columns_are_mapped 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/relationships.py", line 114, in __init__ 
    self._determine_joins() 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/orm/relationships.py", line 180, in _determine_joins 
    consider_as_foreign_keys=consider_as_foreign_keys 
    File "/usr/local/lib/python2.6/dist-packages/SQLAlchemy-0.8.1dev-py2.6-linux-i686.egg/sqlalchemy/sql/util.py", line 345, in join_condition 
    b.foreign_keys, 
AttributeError: type object 'role_user' has no attribute 'foreign_keys' 
>>> 
jiankong@ubuntu:~/git/admin-server$ python manage.py shell 
Python 2.6.5 (r265:79063, Oct 1 2012, 22:07:21) 
[GCC 4.4.3] on linux2 
Type "help", "copyright", "credits" or "license" for more information. 
(InteractiveConsole) 
>>> from apps.auth.models import User 
>>> u1 = User(email='john@example.com', password='12345', name='john') 

我能做些什麼來解決這個問題？謝謝 ！！

Answer 1

你有role_user衝突的名稱，因爲有一個名爲role_user的類和一個同名的表。所以secondary="role_user"首先挑選類對象。也許說出這樣的：

relationship("Role", secondary="role_user.__table__") 

編輯：理想情況下，你會定義「ROLE_USER」因爲只有一張桌子，並定義它，你做的「次級」之前。按照http://docs.sqlalchemy.org/en/latest/orm/relationships.html#many-to-many的示例進行操作。