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Python Django ORM Total Control Annotate

Jay Norris
Jay Norris
14,824 Points
Posted by Jay Norris
Jay Norris
14,824 Points

annotate Avg review

I'm not sure what I'm doing wrong here. Any hints are appreciated.

Challenge Task 1 of 1

I think it's time to have a list view for all of our Products. I've created the URL and template for you and the beginnings of the view. I want the product_list view to list an average rating for each Product. Can you use annotate() and the Avg class (already imported) to add an annotation named avg_rating to the queryset? You'll use "review" instead of "review_set", by the way.

products/views.py 
import datetime

from django.db.models import Q, Avg
from django.shortcuts import render, get_object_or_404

from . import models


def good_reviews(request):
    reviews = models.Review.objects.filter(rating__gte=3)
    return render(request, 'products/reviews.html', {'reviews': reviews})


def recent_reviews(request):
    six_months_ago = datetime.datetime.today() - datetime.timedelta(days=180)
    reviews = models.Review.objects.exclude(created_at__lt=six_months_ago)
    return render(request, 'products/reviews.html', {'reviews': reviews})


def product_detail(request, pk):
    product = get_object_or_404(models.Product, pk=pk)
    four_weeks_ago = datetime.datetime.today() - datetime.timedelta(weeks=4)
    reviews = product.review_set.filter(Q(rating__gte=8)|Q(created_at__gte=four_weeks_ago)).order_by('-created_at').all()
    return render(request, 'products/product_detail.html', {'product': product, 'reviews': reviews})


def product_list(request):
    products = models.Product.objects.all().annotate(avg_rating=Avg('review'))
    return render(request, 'products/product_list.html', {'products': products})

2 Answers

Iain Simmons
Iain Simmons
Treehouse Moderator 32,305 Points

So you need to get the 'rating' property of the 'review' model:

def product_list(request):
    products = models.Product.objects.annotate(avg_rating=Avg('review__rating'))
    return render(request, 'products/product_list.html', {'products': products})
Jay Norris
Jay Norris
14,824 Points
Jay Norris
Jay Norris
14,824 Points

Oh, thank you. I wasn't quite picturing the models correctly.