You want to efficiently load all Author objects with their Book objects, but only books published after 2020. How do you use prefetch_related for this filtered reverse relation?

hard📝 Application Q15 of 15

Django - Caching

You want to efficiently load all Author objects with their Book objects, but only books published after 2020. How do you use prefetch_related for this filtered reverse relation?

authors = Author.objects.prefetch_related( ... )

AUse Prefetch with a filtered queryset: <code>Prefetch('books', queryset=Book.objects.filter(pub_year__gt=2020))</code>

BUse prefetch_related('books').filter(pub_year__gt=2020)

CUse select_related('books').filter(pub_year__gt=2020)

DUse prefetch_related('books__filter(pub_year__gt=2020)')

Step-by-Step Solution

Solution:

Step 1: Understand filtering reverse relations with prefetch_related
To filter related objects in prefetch_related, use the Prefetch object with a filtered queryset.
Step 2: Apply Prefetch with filtered queryset
Use Prefetch('books', queryset=Book.objects.filter(pub_year__gt=2020)) inside prefetch_related() to load only books after 2020.
Final Answer:
Use Prefetch with a filtered queryset: Prefetch('books', queryset=Book.objects.filter(pub_year__gt=2020)) -> Option A
Quick Check:
Filtered prefetch needs Prefetch object [OK]

Quick Trick: Use Prefetch with filtered queryset inside prefetch_related [OK]

Common Mistakes:

MISTAKES

Trying to filter directly inside prefetch_related string
Using select_related for many-to-one reverse relations
Filtering the main queryset instead of related queryset

Master "Caching" in Django

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Perf

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions

More Django Quizzes

You want to efficiently load all Author objects with their Book objects, but only books published after 2020. How do you use prefetch_related for this filtered reverse relation?

Step 1: Understand filtering reverse relations with prefetch_related

Step 2: Apply Prefetch with filtered queryset

Final Answer:

Quick Check:

Want More Practice?