在Django Postgres ArrayField中查找所有没有标签的帖子

Question

Just like what my title says, I want to see all my posts without any tags. However none of the following ORM is working:

x = PostTagging.obejcts.filter(tags=[])
x = PostTagging.objects.filter(tags__len=0)

All I get as a return is:

<QuerySet []>

Here is my model:

class PostTagging(models.Model):
    title = models.CharField(max_length=50)
    tags = ArrayField(models.CharField(max_length=200), blank=True, null=True)

    def __unicode__(self):
        return self.title

Here is my ORM for creating the blank tag:

PostTagging.objects.create(title='Fifth Post')

Answer 1

PostTagging.objects.filter(tags__isnull=True)是最好的方法