fields.py 文件源码

def contribute_to_class(self, cls, name):
        super(Reference, self).contribute_to_class(cls, name)

        # Create ReverseReference in the opposite direction unless related_name ends with '+'
        if not self.related_name or not self.related_name.endswith('+'):
            related_name = self.related_name or '%s_set' % cls.__name__.lower()
            reverse_reference = ReverseReference(cls, field_name=self.field_name, one_to_one=self.one_to_one)
            setattr_lazy(lambda objref=self._objref: lookup_by_objref(objref),
                         related_name, reverse_reference)

        # Allow direct access to the reference without fetching the instance from the server first
        getter = property(curry(self.foo_id_getter, field=self))
        setter = getter.setter(curry(self.foo_id_setter, field=self))
        setattr(cls, '%s_id' % self.field_name, setter)