Django:用另一个表的结果过滤对象?

我对如何在Django做这件事一无所知,希望你能帮忙。

我有一张按类型筛选的库表:

public_galleries = models.Gallery.objects.filter(type = 2).filter(root_gallery__isnull = True)

但我还想看看对于特定用户来说,这个库是否不存在于user gallery表中。我为用户提供了以下库列表:

user_galleries = models.UserGallery.objects.select_related().filter(clientuser=request.user.id).filter(gallery__root_gallery__isnull = True)

注**刚开始将django用于一个真正的项目,因此对这些声明的任何改进都表示赞赏。

编辑-模型:

class Gallery(models.Model):
    """Gallery model"""
    name = models.CharField(u"Gallery name", max_length=120)
    type = models.IntegerField(default=0, choices=TYPE_CHOICES)
    root_gallery = models.ForeignKey("self", blank=True, null=True)
    """ Other Fields"""

class UserGallery(models.Model):
    """Model to link Gallery and ClientUser"""
    gallery = models.ForeignKey(Gallery)
    clientuser = models.ForeignKey(ClientUser)
    owner = models.BooleanField(default=False)