Edit Question - KnowledgeHub

Title Body

suppose I have this model: class PhotoAlbum(models.Model): title = models.CharField(max_length=128) author = models.CharField(max_length=128) class Photo(models.Model): album = models.ForeignKey('PhotoAlbum') format = models.IntegerField() Now if I want to look at a subset of photos in a subset of albums efficiently. I do it something like this: someAlbums = PhotoAlbum.objects.filter(author="Davey Jones").prefetch_related("photo_set") for a in someAlbums: somePhotos = a.photo_set.all() This does only two queries, which is what I expect (one to get the albums, and then one like `SELECT * IN photos WHERE photoalbum_id IN (). Everything is great. But if I do this: someAlbums = PhotoAlbum.objects.filter(author="Davey Jones").prefetch_related("photo_set") for a in someAlbums: somePhotos = a.photo_set.filter(format=1) Then it does a ton of queries with WHERE format = 1 ! Am I doing something wrong or is django not smart enough to realise it has already fetched all the photos and can filter them in python? I swear I read somewhere in the documentation that it is supposed to do that...

Tags (comma-separated) Cancel