django - 从多对一关系中获取对象集

Question

请看看这些型号:

class Album(models.Model):
    user = models.ForeignKey(User)
    name = models.CharField(max_length=200)
    pub_date = models.DateTimeField(default=datetime.now)


class Photo(models.Model):
    album = models.ForeignKey(Album, default=3)
    image = models.ImageField(upload_to=get_upload_file_name)
    caption = models.CharField(max_length=200)
    pub_date = models.DateTimeField(default=datetime.now)

如何获取特定相册的照片集??? 以及如何从照片实例本身获取相册？

我试过这个:

# To get the set of photos from the user (tika) album:
>>>t = User.objects.get(username='tika')
>>>t_album = Album.objects.get(user=t)
>>>t_album 
<Album: tika_album>
>>>t_album.image_set.all()
AttributeError: 'Album' Object has no attribute 'image_set'

请指导我正确的方向.谢谢.

Answer 1

你快到了.你应该用photo_set而不是image_set

>>>t_album.photo_set.all() 

即小写的modelname _set

如果你想要1个查询中的照片列表,

photos = Photo.objects.filter(album__user__username='tika')

Answer 2

更好的是,你可以写 Photo

album = models.ForeignKey(Album, related_name='photos', default=3)

该photos会是相反的字段的名称来自Album于Photo.如果未定义,则将命名反向字段photo_set.

然后你用

t_album.photos.all()  # only if you've defined the `related_name` argument to 'photos'

要么

t_album.photo_set.all()