Python 序列化程序删除Django 3.1中的一对多关系

当我尝试将照片附加到宠物时，序列化程序正在删除附件，我得到的是

附件：[“此字段是必需的”]

。我的代码：

models.py

class Pet(models.Model):
   pet_id = models.UUIDField('pet uid',default=uuid.uuid4,null=False,primary_key=True,blank=False,editable=False, unique=True)  
   name = models.CharField('Pet name', max_length=255, null=False, blank=False)

class Attachment(models.Model):
    attachment_id = models.UUIDField('attachment uid',default=uuid.uuid4,null=False,primary_key=True,blank=False,editable=False, unique=True)       
    pet_id = models.ForeignKey(Pet, on_delete=models.CASCADE)
    name = models.FileField(upload_to='photos/', null=False, blank=False)
    upload_at = models.DateTimeField('Time it was uploaded', max_length=50, null=False, blank=False )

序列化程序.py

class AttachmentSerializer(serializers.ModelSerializer):    
    class Meta:
        model = Attachment
        fields = ('name','upload_at')

class PetSerializer(serializers.ModelSerializer):
    attachment = AttachmentSerializer(source='attachment_set', many=True)
    class Meta: 
        model = Pet
        fields = ('pet_id','name', 'attachment')
    
    # because this: 
    # https://www.django-rest-framework.org/api-guide/relations/#writable-nested-serializers
    def create(self, validated_data):
        attachments = validated_data.pop('attachment')
        pet = Pet.objects.create(**validated_data)
        for att in attachments:
            Attachment.objects.create(pet_id=pet.pet_id, **att)
        return pet

views.py

def create_pet(self, request):      
    serializer = self.get_serializer(data=request.data)         
    if not serializer.is_valid():
       return Response({'error':serializer.errors,status=status.HTTP_400_BAD_REQUEST)

    serializer.save()

    return Response({'data':serializer.validated_data}, status=status.HTTP_201_CREATED) 

    

如果启用

PetSerializer

I do

attachment=AttachmentSerializer（many=True，source=attachment\u set'，required=False）

附件没有问题，但我需要附件

此外，我已在

附件的models.py中完成
pet\u id=models.ForeignKey（pet，related\u name='attachments'，on\u delete=models.CASCADE）
和序列化程序
PetSerializer
：

class PetSerializer(serializers.ModelSerializer):
    class Meta: 
        model = Pet
        fields = ('pet_id','name', 'attachments')

    # because this: 
    # https://www.django-rest-framework.org/api-guide/relations/#writable-nested-serializers
    def create(self, validated_data):
        attachments = validated_data.pop('attachment')
        pet = Pet.objects.create(**validated_data)
        for att in attachments:
            Attachment.objects.create(pet_id=pet.pet_id, **att)
        return pet

但我也犯了同样的错误。
此外，我已经检查了
请求的内容。数据和附件都在那里

有什么想法吗？提前感谢
解决方案是，在序列化程序上将此
附件=AttachmentSerializer（source='attachment_set'，many=True）
更改为
附件=serializers.ListField（child=AttachmentSerializer（many=True））
并在创建方法中添加
附件=attachments[0]
。更新代码：

class PetSerializer(serializers.ModelSerializer):
    attachment = serializers.ListField(child=AttachmentSerializer(many=True))
    class Meta: 
        model = Pet
        fields = ('pet_id','name', 'attachment')
    
    # because this: 
    # https://www.django-rest-framework.org/api-guide/relations/#writable-nested-serializers
    def create(self, validated_data):
        attachments = validated_data.pop('attachment')
        pet = Pet.objects.create(**validated_data)
        attachments = attachments[0] # Extract the list inside the list
        for att in attachments:
            Attachment.objects.create(pet_id=pet.pet_id, **att)
        return pet