Description

========================== django-generic-aggregation ========================== annotate() and aggregate() for generically-related data. also a handy function for filtering GFK-model querysets. Use django's `GenericRelation <https://docs.djangoproject.com/en/dev/ref/contrib/contenttypes/#reverse-generic-relations>`_ where possible, as this can make the queries generated more efficient by using a JOIN rather than a subquery. installation ------------ :: # install from pypi pip install django-generic-aggregation # or install via git pip install -e git+git://github.com/coleifer/django-generic-aggregation.git#egg=generic_aggregation examples -------- The examples below assume the following simple models: :: class Rating(models.Model): rating = models.IntegerField() object_id = models.IntegerField() content_type = models.ForeignKey(ContentType) content_object = GenericForeignKey(ct_field='content_type', fk_field='object_id') class Food(models.Model): name = models.CharField(max_length=50) ratings = generic.GenericRelation(Rating) # reverse generic relation You want to figure out which items are highest rated (generic_annotate) :: from django.db.models import Avg food_qs = Food.objects.filter(name__startswith='a') generic_annotate(food_qs, Rating, Avg('ratings__rating')) # you can mix and match queryset / model generic_annotate(food_qs, Rating.objects.all(), Avg('ratings__rating')) You want the average rating for all foods that start with 'a' (generic_aggregate) :: food_qs = Food.objects.filter(name__startswith='a') generic_aggregate(food_qs, Rating, Avg('ratings__rating')) You want to only display ratings for foods that start with 'a' (generic_filter) food_qs = Food.objects.filter(name__startswith='a') generic_filter(Rating.objects.all(), food_qs) documentation ------------- http://django-generic-aggregation.readthedocs.org/