Question

我有两个课程，TrialIdentifier和TimeCourse

TimeCourse有一个包含TrialIdentifier的实例变量，我试图在两者之间建立外键关系。

在TrialIdentifier

中

__tablename__ = 'trial_identifiers'

relationships = relationship('TimeCourse', 
                             back_populates = 'trial_identifier', uselist = False)

在TimeCourse中

__tablename__ = 'time_course'

trial_identifier_id = Column(Integer, ForeignKey('trial_identifiers.id'))
trial_identifier = relationship('TrialIdentifier', back_populates = 'relationships')`

如果我在trial_identifier中命名变量TimeCourse，则会引发以下错误：

sqlalchemy.exc.InvalidRequestError: Mapper 'Mapper|TimeCourse|time_course' has no property 'trial_identifier'

如果我将其他名称命名，一切正常。整个包都是基于TimeCourse().trial_identifier构建的，所以我希望尽可能避免重构。或至少了解这种行为。

Answer 1

trial_identifier是一个私有变量，定义为trial_identifier = relationship('TrialIdentifier', back_populates = 'relationships')`

删除setter和getter，或替换

_trial_identifier = relationship('TrialIdentifier', back_populates = 'relationships')`

与

A a = new A();
a->fun1("one");
a->fun2(1, 2);
...
a->fun10("end");

解决了问题

sqlalchemy.exc.InvalidRequestError：Mapper＆＃39; ...＆＃39;没有财产＆＃39; ...＆＃39;

1 个答案: