“Django”列中的空值；“用户id”；违反非空约束

我有一个模型用户首选项，它引用了Django模型用户。我不断地犯错误：

IntegrityError:user\u id列中的null值违反了not null约束
详细信息：失败的行包含（dfac4cb7-0bdb-44e4-b951-c0c9386bf143，f，null）

尝试发布新用户首选项时。我为邮寄发送的数据是：

{
    "user": "http://127.0.0.1:8000/user/4/",
    "send_email": false
}

我的用户偏好模型是：

import uuid
from django.db import models
from django.contrib.auth.models import User


class UserPreference(models.Model):
    class Meta:
        app_label = 'my_app'
        permissions = (
            ('view_userpreference', 'View User Preference'),
        )

    uuid = models.UUIDField(primary_key=True, editable=False, default=uuid.uuid4)
    user = models.OneToOneField(User, related_name="user_preference", on_delete=models.CASCADE, db_index=True)
    send_email = models.BooleanField(default=True, db_index=True)


    def __unicode__(self):
        return u"<UserPreference {0} {1}>".format(str(self.uuid), self.user.id)

我的userpreference序列化程序是：

class UserPreferenceSerializer(serializers.HyperlinkedModelSerializer):
    user = serializers.HyperlinkedRelatedField(view_name='user-detail', read_only=True, lookup_field="id", lookup_url_kwarg="pk")

    class Meta:
        model = UserPreference
        fields = ('url',
                  'user',
                  'send_email')


class UserPreferenceListSerializer(serializers.HyperlinkedModelSerializer):
    user = serializers.HyperlinkedRelatedField(view_name='user-detail', read_only=True, lookup_field="id", lookup_url_kwarg="pk")

    class Meta:
        model = UserPreference
        fields = ('url',
                  'user',
                  'send_email')

有什么建议吗

编辑：将post方法添加到我的视图解决了这个问题。在UserPreferenceList类中，我添加了：

def post(self, request, *args, **kwargs):
    user_url = request.data.get('user', None)
    if user_url:
        try:
            path = urlparse.urlparse(user_url).path
            match = resolve(path)
            user_pk = match.kwargs.get('pk')
        except (Resolver404, User.DoesNotExist) as e:
            raise CustomAPIException("You need to send the url of a User to create its UserPreference.", status=status.HTTP_400_BAD_REQUEST)
    else:
        raise CustomAPIException("You need to identify a User to create its UserPreference.", status=status.HTTP_400_BAD_REQUEST)

    userpreference_obj = UserPreference(user_id=user_pk, send_email=request.data.get('send_email', False))
    userpreference_obj.save()
    d = UserPreferenceSerializer(userpreference_obj, context={'request': request}).data
    return Response(d, status=status.HTTP_201_CREATED)

---

这是因为这里的这一行：

user = models.OneToOneField(User, related_name="user_preference", on_delete=models.CASCADE, db_index=True)

在

UserPreference

Model

中，当您指定该字段/关系时，您的意思是

用户必须存在外键。一个没有，所以你得到了那个错误

在POST或create方法中，将
user
指定为整数
id
，因为它是主键

user = models.OneToOneField(User, related_name="user_preference", on_delete=models.CASCADE, db_index=True)