Prefetch_related for reverse relations in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to prefetch the reverse relation 'books' for all authors.

Django

authors = Author.objects.all().[1]('books')

Drag options to blanks, or click blank then click option'

Afilter

Bprefetch_related

Cselect_related

Dannotate

Attempts:

3 left

💡 Hint

Common Mistakes

Using select_related instead of prefetch_related for reverse relations.

Forgetting to specify the related name 'books'.

Use prefetch_related to efficiently fetch reverse relations like 'books' for authors.

2fill in blank

medium

Complete the code to prefetch the reverse relation 'comments' on a queryset of posts.

Django

posts = Post.objects.all().[1]('comments')

Drag options to blanks, or click blank then click option'

Aorder_by

Bannotate

Cprefetch_related

Dvalues

Attempts:

3 left

💡 Hint

Common Mistakes

Using annotate which is for aggregation, not fetching related objects.

Using order_by which only sorts the queryset.

prefetch_related is used to fetch reverse relations like 'comments' efficiently.

3fill in blank

hard

Fix the error in the code to correctly prefetch the reverse relation 'orders' for customers.

Django

customers = Customer.objects.all().[1]('order_set')

Drag options to blanks, or click blank then click option'

Aselect_related

Bexclude

Cfilter

Dprefetch_related

Attempts:

3 left

💡 Hint

Common Mistakes

Using select_related which only works for forward foreign keys.

Using incorrect related name instead of 'order_set'.

Use prefetch_related with the default reverse relation name 'order_set' to fetch orders for customers.

4fill in blank

hard

Fill both blanks to prefetch the reverse relation 'reviews' and filter only those with rating greater than 3.

Django

products = Product.objects.all().prefetch_related([1]('reviews', queryset=Review.objects.filter(rating [2] 3)))

Drag options to blanks, or click blank then click option'

APrefetch

B>

C<

Dselect_related

Attempts:

3 left

💡 Hint

Common Mistakes

Using select_related instead of Prefetch for custom queryset.

Using wrong comparison operator in filter.

Use Prefetch to customize the prefetch with a filtered queryset, and use > to filter ratings greater than 3.

5fill in blank

hard

Fill all three blanks to prefetch reverse relation 'entries' with a filtered queryset, and order the entries by 'date'.

Django

blogs = Blog.objects.all().prefetch_related([1]('entries', queryset=Entry.objects.filter(status=[2]).order_by([3])))

Drag options to blanks, or click blank then click option'

APrefetch

B'published'

C'date'

Dselect_related

Attempts:

3 left

💡 Hint

Common Mistakes

Using select_related instead of Prefetch.

Forgetting to quote string values in filter and order_by.

Use Prefetch to customize the prefetch, filter entries with status 'published', and order by 'date'.