序列化程序在 Django 3.1 中删除一对多关系

Question

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 attachment :['This field is required']。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 )

serializers.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 PetSerializer 我会 attachment = AttachmentSerializer(many=True, source='attachment_set', required=False) 附件没有问题，但我需要附件。

我也在models.py上做了Attachment pet_id = models.ForeignKey(Pet, related_name='attachments', on_delete=models.CASCADE) 和序列化器 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

但我得到了同样的错误。另外我检查了request.data的内容，附件在里面。

对此有什么想法吗？提前致谢

Answer 1

解决方案是，在序列化程序上将此 attachment = AttachmentSerializer(source='attachment_set', many=True) 更改为 attachment = serializers.ListField(child=AttachmentSerializer(many=True)) 并添加创建方法 attachments = 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

序列化程序在 Django 3.1 中删除一对多关系

Serializer removing one to many relationship in Django 3.1

python

django

django-serializer