child.parent_cover_changed()
book.save() # update sort_key_author
+ book.update_popularity()
cls.published.send(sender=cls, instance=book)
return book
class BookPopularity(models.Model):
book = models.OneToOneField(Book, related_name='popularity')
- count = models.IntegerField(default=0)
+ count = models.IntegerField(default=0, db_index=True)