Using prefetch_related for Optimization

# models.py

from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=100)

    def __str__(self):
        return self.name

class Book(models.Model):
    title = models.CharField(max_length=200)
    authors = models.ManyToManyField(Author, related_name='books')

    def __str__(self):
        return self.title
  

# views.py

from django.shortcuts import render
from .models import Book

def book_list_without_prefetch(request):
    books = Book.objects.all()  # This will cause N+1 queries when accessing authors
    book_info = [(book.title, [author.name for author in book.authors.all()]) for book in books]
    return render(request, 'books.html', {'book_info': book_info})
    # Each book.authors.all() triggers extra queries

def book_list_with_prefetch(request):
    books = Book.objects.prefetch_related('authors')  # Efficiently fetches related authors
    book_info = [(book.title, [author.name for author in book.authors.all()]) for book in books]
    return render(request, 'books.html', {'book_info': book_info})
    # Authors are prefetched; no extra queries per book