python - Django检查相关对象是否存在错误: RelatedObjectDoesNotExist

Question

我的模型中有一个方法 has_related_object 需要检查相关对象是否存在

class Business(base):
      name =  models.CharField(max_length=100, blank=True, null=True)

  def has_related_object(self):
        return (self.customers is not None) and (self.car is not None)


class Customer(base):
      name =  models.CharField(max_length=100, blank=True, null=True)
      person = models.OneToOneField('Business', related_name="customer")

但我得到了错误:

Business.has_related_object()

RelatedObjectDoesNotExist: Business has no customer.

Answer 1

使用 hasattr(self, 'customers') 避免异常检查为 recommended in Django docs :

def has_related_object(self):
    return hasattr(self, 'customers') and self.car is not None