Relationship query patterns in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get all books written by an author with id 1.

Django

books = Book.objects.filter(author__[1]=1)

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

Aid

Bname

Ctitle

Dpk

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'name' instead of 'id' causes no results if filtering by author id.

Using 'title' is wrong because it's a Book field, not Author.

The double underscore syntax lets you filter by fields of related models. Here, author__id=1 filters books whose author's id is 1.

2fill in blank

medium

Complete the code to get all authors who have written a book titled 'Django Basics'.

Django

authors = Author.objects.filter(book__[1]='Django Basics')

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

Aname

Bid

Cauthor

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'name' filters by author name, not book title.

Using 'author' is invalid because it's a reverse relation here.

We filter authors by the title of their related books using book__title='Django Basics'.

3fill in blank

hard

Fix the error in the code to get all books with at least one review rating greater than 4.

Django

books = Book.objects.filter(review__[1]__gt=4)

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

Arating

Bscore

Crate

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'score' or 'value' causes errors if those fields don't exist.

Using 'rate' is incorrect if the model field is named 'rating'.

The related Review model has a field named 'rating'. Using review__rating__gt=4 filters books with reviews rated above 4.

4fill in blank

hard

Fill both blanks to get all authors who have written more than 3 books.

Django

authors = Author.objects.annotate(book_count=[1]).filter(book_count__[2]=3)

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

ACount('book')

BSum('book')

Cgt

Dlt

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Sum' instead of 'Count' aggregates incorrectly.

Using 'lt' filters authors with fewer than 3 books, opposite of requirement.

We use annotate with Count('book') to count books per author, then filter authors with book_count greater than 3 using book_count__gt=3.

5fill in blank

hard

Fill all three blanks to get all books with reviews rated at least 4 and order them by author's name.

Django

books = Book.objects.filter(review__[1]__[2]=4).order_by('[3]')

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

Arating

Bgte

Cauthor__name

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'gt' instead of 'gte' excludes reviews rated exactly 4.

Ordering by 'title' orders by book title, not author's name.

Filter books with reviews having rating greater or equal to 4 using review__rating__gte=4. Then order by author's name with order_by('author__name').