class myClass (models.Model):
related_operation = models.ForeignKey('self', null = True)
__related_operation = None
def save(self, force_insert=False, force_update=False):
if self.related_operation != self.__related_operation:
del self.__related_operation
super(Operation, self).save(force_insert, force_update)
self.__related_operation = self.related_operation
我应该使用 del self.__related_operation 还是应该使用 self.__related_operation.delete()?