👀 Views: 2 💬 Answers: 1 📅 Created: 2025-06-05

django orm performance

I'm working with Django 3.2 and trying to optimize my database queries using `prefetch_related`, but I'm still seeing an unexpected number of queries when accessing related objects. My model structure includes a `Book` model that has a foreign key to an `Author` model, and I want to fetch all books along with their authors efficiently. Here's a simplified version of my models: ```python class Author(models.Model): name = models.CharField(max_length=100) class Book(models.Model): title = models.CharField(max_length=200) author = models.ForeignKey(Author, on_delete=models.CASCADE) ``` In my view, I'm using the following query to fetch books with their authors: ```python from .models import Book from django.shortcuts import render def book_list(request): books = Book.objects.prefetch_related('author').all() return render(request, 'books/book_list.html', {'books': books}) ``` However, when I check the number of queries being executed using the Django Debug Toolbar, I see that it’s still executing one query per book to fetch the author data. I expected it to reduce the query count significantly. I've also tried using `select_related` in place of `prefetch_related`, thinking it might help since the relationship is a simple foreign key, but it didn't make much of a difference either. Is there something I might be missing in my implementation, or is there a specific scenario where `prefetch_related` does not work as intended? Any advice on how to properly optimize this would be greatly appreciated!