👀 Views: 2 💬 Answers: 1 📅 Created: 2025-06-10

django bulk_create models related_fields Python

Hey everyone, I'm running into an issue that's driving me crazy... I'm facing an issue with Django where after using `bulk_create` to add multiple instances of a model, the related fields in another model are not being updated as expected. I have two models, `Author` and `Book`. When I create several `Book` instances for an `Author` using `bulk_create`, the `Author` instance's `book_count` field (which is a field that counts the number of books) does not reflect the new additions correctly. Here's the relevant code: ```python from django.db import models, transaction class Author(models.Model): name = models.CharField(max_length=100) book_count = models.IntegerField(default=0) class Book(models.Model): title = models.CharField(max_length=100) author = models.ForeignKey(Author, related_name='books', on_delete=models.CASCADE) # Function to add books to an author def add_books_to_author(author_id, book_titles): author = Author.objects.get(id=author_id) new_books = [Book(title=title, author=author) for title in book_titles] Book.objects.bulk_create(new_books) # This line is not correctly updating the book_count author.book_count += len(new_books) author.save() ``` After executing `add_books_to_author`, the `book_count` does not seem to increment as expected. I have tried using a transaction to ensure that the operations are atomic, but it still doesn't reflect the correct count in the database. I also checked that the `author` object is indeed the correct instance before the update. Could anyone provide insight into whether `bulk_create` affects the related model's fields immediately, or do I need to handle this differently? I'm using Django 3.2.12. Am I missing something obvious? For context: I'm using Python on Debian. I'm on Ubuntu 20.04 using the latest version of Python. Any feedback is welcome!