Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Django ORM Total Control prefetch_related

Posted by Chris Couch
.a{fill-rule:evenodd;}techdegree seal-36
Chris Couch
Front End Web Development Techdegree Graduate 25,326 Points

We can't stop the query in product_detail for the Reviews that belong to a Product, but we can move it up so it's done a

Bummer: Didn't get a 200!

not sure what i'm missing

products/views.py 
import datetime

from django.db.models import Q, Avg
from django.http import Http404
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):
    try:
        product = get_object_or_404(models.Product.objects.get(pk=pk))
    except models.Product.DoesNotExist:
        raise Http404('')

    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.annotate(avg_rating=Avg('review__rating')).all()
    return render(request, 'products/product_list.html', {'products': products})