Flask程序错误的log：
[2016-10-20 16:04:34 +0000] [20504] [ERROR] Error handling request /runningfast/api/v1.0/open/accesstoken Traceback (most recent call last): File "/root/Envs/RunningFast/lib/python2.7/site-packages/gunicorn/workers/sync.py", line 135, in handle self.handle_request(listener, req, client, addr) File "/root/Envs/RunningFast/lib/python2.7/site-packages/gunicorn/workers/sync.py", line 176, in handle_request respiter = self.wsgi(environ, resp.start_response) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 2000, in __call__ return self.wsgi_app(environ, start_response) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1991, in wsgi_app response = self.make_response(self.handle_exception(e)) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_restful/__init__.py", line 271, in error_router return original_handler(e) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1567, in handle_exception reraise(exc_type, exc_value, tb) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_restful/__init__.py", line 268, in error_router return self.handle_error(e) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1988, in wsgi_app response = self.full_dispatch_request() File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1641, in full_dispatch_request rv = self.handle_user_exception(e) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_restful/__init__.py", line 271, in error_router return original_handler(e) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1544, in handle_user_exception reraise(exc_type, exc_value, tb) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_restful/__init__.py", line 268, in error_router return self.handle_error(e) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1639, in full_dispatch_request rv = self.dispatch_request() File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/app.py", line 1625, in dispatch_request return self.view_functions[rule.endpoint](**req.view_args) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_restful/__init__.py", line 477, in wrapper resp = resource(*args, **kwargs) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask/views.py", line 84, in view return self.dispatch_request(*args, **kwargs) File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_restful/__init__.py", line 587, in dispatch_request resp = meth(*args, **kwargs) File "/root/RunningFast/staging/runningfast/resources/Accesstoken.py", line 193, in post foundUser = User.query.filter_by(phone=phone).first() File "/root/Envs/RunningFast/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py", line 498, in __get__ mapper = orm.class_mapper(type) File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/base.py", line 421, in class_mapper mapper = _inspect_mapped_class(class_, configure=configure) File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/base.py", line 400, in _inspect_mapped_class mapper._configure_all() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/mapper.py", line 1222, in _configure_all configure_mappers() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/mapper.py", line 2840, in configure_mappers mapper._post_configure_properties() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/mapper.py", line 1765, in _post_configure_properties prop.init() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/interfaces.py", line 183, in init self.do_init() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 1653, in do_init self._setup_join_conditions() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 1728, in _setup_join_conditions can_be_synced_fn=self._columns_are_mapped File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 1986, in __init__ self._determine_joins() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 2113, in _determine_joins % self.prop) AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship Task.initiator – there are multiple foreign key paths linking the tables. Specify the ‘foreign_keys’ argument, providing a list of those columns which should be counted as containing a foreign key reference to the parent table. [2016-10-20 16:04:46 +0000] [20488] [INFO] Handling signal: term |
对应代码：
foundUser = User.query.filter_by(phone=phone).first() gLog.debug(‘foundUser=%s’, foundUser) |
对应的SQLAlchemy的数据模型定义：
/Users/crifan/dev/dev_root/daryun/Projects/RunningFast/sourcecode/RunningFast-Server/runningfast/models/init.py
class User(db.Model): __tablename__ = ‘users’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("user-"), nullable=False) tasks = db.relationship(‘Task’, back_populates=’initiator’) orders = db.relationship(‘Task’, back_populates=’errandor’) class Task(db.Model): __tablename__ = ‘tasks’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("task-"), nullable=False) initiatorId = db.Column(db.String(64), db.ForeignKey("users.id")) errandorId = db.Column(db.String(64), db.ForeignKey("users.id")) # initiator = db.relationship(‘User’, foreign_keys=initiatorId) # errandor = db.relationship(‘User’, foreign_keys=errandorId) initiator = db.relationship(‘User’, back_populates="tasks") errandor = db.relationship(‘User’, back_populates="orders") |
搜：
Flask SQLAlchemy AmbiguousForeignKeysError Could not determine join condition between
python – sqlalchemy foreign key relationship attributes – Stack Overflow
Configuring how Relationship Joins — SQLAlchemy 1.1 Documentation
去改为：
initiatorId = db.Column(db.String(64), db.ForeignKey("users.id")) errandorId = db.Column(db.String(64), db.ForeignKey("users.id")) initiator = db.relationship(‘User’, back_populates="tasks", foreign_keys=[initiatorId]) errandor = db.relationship(‘User’, back_populates="orders", foreign_keys=[errandorId]) |
好像是可以了。
不过又出现类似的问题：
[2016-10-20 16:49:12 +0000] [21430] [ERROR] Error handling request … self._setup_join_conditions() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 1728, in _setup_join_conditions can_be_synced_fn=self._columns_are_mapped File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 1986, in __init__ self._determine_joins() File "/root/Envs/RunningFast/lib/python2.7/site-packages/sqlalchemy/orm/relationships.py", line 2113, in _determine_joins % self.prop) AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship Location.initiatorStartLocationTask – there are multiple foreign key paths linking the tables. Specify the ‘foreign_keys’ argument, providing a list of those columns which should be counted as containing a foreign key reference to the parent table. |
然后再去看看对应的Location.initiatorStartLocationTask：
class Location(db.Model): __tablename__ = ‘locations’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("location-"), nullable=False) longitude = db.Column(db.Float, nullable=False, default = 0.0) latitude = db.Column(db.Float, nullable=False, default=0.0) shortStr = db.Column(db.String(64), nullable=False, default = "") fullStr = db.Column(db.String(256), nullable=False, default="") initiatorStartLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) initiatorStartLocationTask = db.relationship("Task", back_populates="initiatorStartLocation") initiatorEndLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) initiatorEndLocationTask = db.relationship("Task", back_populates="initiatorEndLocation") errandorStartLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) errandorStartLocationTask = db.relationship("Task", back_populates="errandorStartLocation") errandorEndLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) errandorEndLocationTask = db.relationship("Task", back_populates="errandorEndLocation") class Task(db.Model): __tablename__ = ‘tasks’ initiatorStartLocation = db.relationship(‘Location’, uselist=False, back_populates="initiatorStartLocationTask") initiatorEndLocation = db.relationship(‘Location’, uselist=False, back_populates="initiatorEndLocationTask") |
所以去改为：
initiatorStartLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) initiatorStartLocationTask = db.relationship("Task", back_populates="initiatorStartLocation", foreign_keys=[initiatorStartLocationTaskId]) initiatorEndLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) initiatorEndLocationTask = db.relationship("Task", back_populates="initiatorEndLocation", foreign_keys=[initiatorEndLocationTaskId]) errandorStartLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) errandorStartLocationTask = db.relationship("Task", back_populates="errandorStartLocation", foreign_keys=[errandorStartLocationTaskId]) errandorEndLocationTaskId = db.Column(db.String(64), db.ForeignKey("tasks.id")) errandorEndLocationTask = db.relationship("Task", back_populates="errandorEndLocation", foreign_keys=[errandorEndLocationTaskId]) |
【总结】
当一个表中出现多个：
ForeignKey
则SQLAlchemy无法识别，具体哪个属性，从哪个去找，所以报错：
AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship Task.initiator
解决办法：
给db.relationship添加foreign_keys，就可以指明具体是哪个属性了。
即，将：
class User(db.Model): __tablename__ = ‘users’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("user-"), nullable=False) tasks = db.relationship(‘Task’, back_populates=’initiator’) orders = db.relationship(‘Task’, back_populates=’errandor’) class Task(db.Model): __tablename__ = ‘tasks’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("task-"), nullable=False) initiatorId = db.Column(db.String(64), db.ForeignKey("users.id")) errandorId = db.Column(db.String(64), db.ForeignKey("users.id")) # initiator = db.relationship(‘User’, foreign_keys=initiatorId) # errandor = db.relationship(‘User’, foreign_keys=errandorId) initiator = db.relationship(‘User’, back_populates="tasks") errandor = db.relationship(‘User’, back_populates="orders") |
改为：
class User(db.Model): __tablename__ = ‘users’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("user-"), nullable=False) tasks = db.relationship(‘Task’, back_populates=’initiator’) orders = db.relationship(‘Task’, back_populates=’errandor’) class Task(db.Model): __tablename__ = ‘tasks’ id = db.Column(db.String(64), primary_key=True, default = generateUUID("task-"), nullable=False) initiatorId = db.Column(db.String(64), db.ForeignKey("users.id")) errandorId = db.Column(db.String(64), db.ForeignKey("users.id")) initiator = db.relationship(‘User’, back_populates="tasks", foreign_keys=[initiatorId]) errandor = db.relationship(‘User’, back_populates="orders", foreign_keys=[errandorId]) |
即可。
转载请注明：在路上 » 【已解决】Flask中SQLAlchemy出错：AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship