Field lookups (exact, contains, gt, lt) in Django - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What does this Django query return?

Consider a Django model Book with a field title. What does this query return?

Book.objects.filter(title__contains='django')

A All books with titles that include the exact word 'django' only

B All books with titles that contain the substring 'django' anywhere, case-insensitive

C All books with titles that contain the substring 'django' anywhere, case-sensitive

D All books with titles exactly equal to 'django'

💡 Hint

Think about whether the lookup is case-sensitive or not.

The '__contains' lookup in Django filters for records where the field contains the given substring exactly as typed, so it is case-sensitive.

📝 Syntax

intermediate

Which query correctly filters for books published after 2010?

Given a Django model Book with a field published_year (integer), which query correctly filters books published after 2010?

A Book.objects.filter(published_year__after=2010)

B Book.objects.filter(published_year>2010)

C Book.objects.filter(published_year__gte=2010)

D Book.objects.filter(published_year__gt=2010)

💡 Hint

Look for the correct Django field lookup suffix for 'greater than'.

The correct lookup for 'greater than' in Django ORM is '__gt'. The option with '__gte' means 'greater than or equal to', which is not the same.

🔧 Debug

advanced

Why does this query raise an error?

Given a Django model Author with a field name, why does this query raise an error?

Author.objects.filter(name__contains)

A Because the '__contains' lookup requires a value to compare against, but none was provided

B Because '__contains' is not a valid Django lookup

C Because 'name' field does not support lookups

D Because the query should use '__icontains' instead

💡 Hint

Check the syntax of the filter method and its arguments.

The '__contains' lookup requires a value to compare the field against. Omitting the value causes a TypeError.

❓ state_output

advanced

What is the count of books returned?

Assume the database has these Book titles:
- 'Django for Beginners'
- 'Learning Python'
- 'Advanced Django'
- 'Python Cookbook'

What is the count of books returned by:
Book.objects.filter(title__exact='Django for Beginners').count()

A 2

B 1

C 0

D 4

💡 Hint

The '__exact' lookup matches the whole field exactly.

Only one book title exactly matches 'Django for Beginners'.

🧠 Conceptual

expert

Which lookup is case-insensitive for substring matching?

You want to filter a Django model's text field to find records containing a substring regardless of case. Which lookup should you use?

A __icontains

B __exact

C __contains

D __iexact

💡 Hint

Look for the lookup with 'i' prefix for case-insensitive.

The '__icontains' lookup performs a case-insensitive substring match.