type object 'X' has no attribute 'obje

问题:

I am using Django and Django Rest Framework 2.4.0

I get the Attribute error type object 'Notification' has no attribute 'objects'

models.py

class Notification(models.Model):
    NOTIFICATION_ID = models.AutoField(primary_key=True)
    user = models.ForeignKey(User, related_name='user_notification')
    type = models.ForeignKey(NotificationType)
    join_code = models.CharField(max_length=10, blank=True)
    requested_userid = models.CharField(max_length=25, blank=True)
    datetime_of_notification = models.DateTimeField()
    is_active = models.BooleanField(default=True)

serializers.py:

class NotificationSerializer(serializers.ModelSerializer):
    class Meta:
        model = Notification
        fields = (
            'type',
            'join_code',
            'requested_userid',
            'datetime_of_notification'
        )

api.py:

class Notification(generics.ListAPIView):
    serializer_class = NotificationSerializer
    def get_queryset(self):
        notifications = Notification.objects.all()
        return notifications

Can anybody help me to figure this out? It fails in api.py at the line notifications = Notification.objects.all()

回答1:

The line notifications = Notification.objects.all() is referencing the Notification class defined in api.py and not models.py.

The easiest way to fix this error is to rename the Notification class in either api.py or models.py so that you can refer to your model properly. Another option would be to use named imports:

from .models import Notification as NotificationModel

class Notification(generics.ListAPIView):
    ...
    def get_queryset(self):
        notifications = NotificationModel.objects.all()
        ...

回答2:

Add objects = models.Manager() to your model, or any other custom manager that you are using and/or define.

class Notification(models.Model):
    NOTIFICATION_ID = models.AutoField(primary_key=True)
    user = models.ForeignKey(User, related_name='user_notification')
    type = models.ForeignKey(NotificationType)
    join_code = models.CharField(max_length=10, blank=True)
    requested_userid = models.CharField(max_length=25, blank=True)
    datetime_of_notification = models.DateTimeField()
    is_active = models.BooleanField(default=True)

    objects = models.Manager()