Solution:Step 1: Analyze query behavior without select_relatedWithout select_related, accessing book.author triggers a separate query per book.Step 2: Understand impact on performanceThis causes many queries, slowing down the app (N+1 query problem).Final Answer:It will execute one query per book to

[Solved] Consider this code:books = Book.objects.all() for book in books: print(book.author.name)What is the main problem with this code if select_related is not used? | Django

Django - Caching

Consider this code:

books = Book.objects.all()
for book in books:
    print(book.author.name)

What is the main problem with this code if select_related is not used?

AIt will execute one query per book to fetch the author.

BIt will raise a syntax error.

CIt will fetch all authors in a single query.

DIt will not fetch any authors.

Step-by-Step Solution

Solution:

Step 1: Analyze query behavior without select_related
Without select_related, accessing book.author triggers a separate query per book.
Step 2: Understand impact on performance
This causes many queries, slowing down the app (N+1 query problem).
Final Answer:
It will execute one query per book to fetch the author. -> Option A
Quick Check:
No select_related = many queries [OK]

Quick Trick: Without select_related, related access causes many queries [OK]

Common Mistakes:

MISTAKES

Thinking it raises syntax errors
Assuming authors are fetched in one query automatically

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Consider this code:

Step 1: Analyze query behavior without select_related

Step 2: Understand impact on performance

Final Answer:

Quick Check:

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