尝试在序列化程序“HealthQuotationSerializer”上获取字段“members”的值时出现 AttributeError答案

【问题标题】：Got AttributeError when attempting to get a value for field `members` on serializer `HealthQuotationSerializer`尝试在序列化程序“HealthQuotationSerializer”上获取字段“members”的值时出现 AttributeError
【发布时间】：2021-02-07 07:52:03
【问题描述】：

尝试序列化父子模型。这是我的模型：

class HealthQuotation(models.Model):
  quotation_no = models.CharField(max_length=50)
  insuredpersons = models.IntegerField()
  mobile_no = models.CharField(max_length=10)

  def __str__(self):
      return self.quotation_no

class HealthQuotationMember(models.Model):
   premium = models.FloatField(null=True)
   suminsured = models.FloatField()
   quotation = models.ForeignKey(HealthQuotation,on_delete=models.CASCADE)

   def __str__(self):
     return str(self.quotation)

这是我的序列化程序：

class HealthQuotationMemberSerializer(serializers.ModelSerializer):
  class Meta:
    model = HealthQuotationMember
    fields= "__all__"

class HealthQuotationSerializer(serializers.ModelSerializer):
   members = HealthQuotationMemberSerializer(many=True)

   class Meta:
      model = HealthQuotation
      fields = ['id','members']

在使用父序列化程序序列化父模型时，Django 在尝试获取序列化程序 HealthQuotationSerializer 上字段 members 的值时抛出错误“Got AttributeError”。序列化程序字段可能命名不正确，并且与HealthQuotation 实例。原始异常文本为：“HealthQuotation”对象没有属性”。

【问题讨论】：

标签： django django-models django-rest-framework django-views django-serializer

【解决方案1】：

因为您的模型中没有 members 字段...尝试按以下方式更改您的序列化程序，看看它是否有效：

class HealthQuotationSerializer(serializers.ModelSerializer):
   quotation = HealthQuotationMemberSerializer()

   class Meta:
      model = HealthQuotation
      fields = ['id','quotation']

请注意，我已删除 many=True，因为每个数据 (ForeignKey) 总会有一个对象。当您有多个对象时，例如Many2Many，您应该使用many=True。

【讨论】：

【解决方案2】：

您有“HealthQuotation”作为父母和“HealthQuotationMember”作为孩子。

现在，您决定从父级“HealthQuotation”检索数据
及其相关的孩子将来自“HealthQuotationMember”，对吧？

要实现这一点，您可以使用 Django SerializerMethodField():

您的 serializers.py 应如下所示：

class HealthQuotationMemberSerializer(serializers.ModelSerializer):
    class Meta:
        model = HealthQuotationMember
        fields= '__all__'

class HealthQuotationSerializer(serializers.ModelSerializer):

    members = serializers.SerializerMethodField() # I am using SerializerMethodField()

    class Meta:
        model = HealthQuotation
        fields = '__all__'

    def get_members(self, quotation):
        
        q = HealthQuotationMember.objects.filter(quotation = quotation)
        
        serializer = HealthQuotationMemberSerializer(q, many=True)
        return serializer.data

你的意见.py

class GetHealthQuotationList(ListAPIView):
    
    serializer_class = HealthQuotationSerializer
    queryset = HealthQuotation.objects.all()

你的 url.py 应该是：

path('get-health-quotation-list', GetHealthQuotationList.as_view()),

注意：如果您计划从child 表中检索数据并找到其关联的parent，那么您的序列化程序应该可以不用many=True 参数。

【讨论】：