Django REST Framework NOT NULL约束失败

Question

当我试图通过发布以下JSON:来创建新的Post时

{
"text": "test",
"location": 1
}

我得到以下错误：

NOT NULL constraint failed: grapevineapp_post.location_id

models.py:

class Location(models.Model):
name = models.CharField(max_length=80)
created = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.name
class Post(models.Model):
text = models.CharField(max_length=512)
owner = models.ForeignKey('auth.User', related_name='posts', on_delete=models.CASCADE)
location = models.ForeignKey(Location, related_name='posts', on_delete=models.CASCADE)
created = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.text

views.py:

class PostList(generics.ListCreateAPIView):
permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
queryset = Post.objects.all()
serializer_class = PostSerializer
def perform_create(self, serializer):
serializer.save(owner=self.request.user)
class PostDetail(generics.RetrieveUpdateDestroyAPIView):
permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
queryset = Post.objects.all()
serializer_class = PostSerializer

序列化程序.py

class PostSerializer(serializers.Serializer):
id = serializers.IntegerField(read_only=True)
text = serializers.CharField(required=False, allow_blank=True, max_length=512)
owner = serializers.ReadOnlyField(source='owner.username')
location = serializers.PrimaryKeyRelatedField(many=False, read_only=True)
def create(self, validated_data):
return Post.objects.create(**validated_data)
def update(self, instance, validated_data):
instance.text = validated_data.get('text', instance.text)
instance.location = validated_data.get('location', instance.location)
instance.save()
return instance
class UserSerializer(serializers.ModelSerializer):
posts = serializers.PrimaryKeyRelatedField(many=True, queryset=Post.objects.all())
class Meta:
model = User
fields = ('id', 'username', 'posts')

DB已被清除。位置是通过使用管理界面创建的。我知道这个问题很琐碎，但我就是做不到。

Answer 1

为了详细说明Willem Van Onsem所说的内容，您将PostSerializer.location字段设置为read-only。您为其提供的json数据将被忽略(文档(，即它不会包含在validated_data中。

然后，当您在create方法中调用Post.objects.create(**validated_data)时，它会尝试创建一个不带位置参数的Post实例，但会出现错误。

编辑：在您上面关于queryset的评论之后。

您需要为它提供一个查询集，以便根据(文档(进行验证。在您的情况下，您想要

location = serializers.PrimaryKeyRelatedField(
many=False,
queryset=Location.objects.all()
)