Resolving the AttributeError: 'int' object has no attribute 'pk' in Django REST Framework

Learn how to fix the common `AttributeError: 'int' object has no attribute 'pk'` when working with multiple foreign keys in Django models. This guide offers step-by-step instructions and explanations to enhance your understanding.
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Fixing AttributeError: 'int' object has no attribute 'pk' in Django REST Framework

If you are developing an application using Django and the Django REST Framework (DRF) and have encountered the error message:

[[See Video to Reveal this Text or Code Snippet]]

You are not alone! This is a common issue, particularly when you have multiple foreign keys pointing to the same model. In this post, we will explore the cause of this error and how to resolve it effectively.

Understanding the Problem

The error you are encountering suggests that there is an attempt to access a property (pk or primary key) on an integer value. This typically occurs when a foreign key relationship is incorrectly handled in your queries or serialization process.

To illustrate, let's dive into our example where we have a Django model defined for OrderProductsModel containing two foreign keys to the CustomUser model:

Model Definition

[[See Video to Reveal this Text or Code Snippet]]

The issue arises in your view, specifically in the get_seller method where you attempt to set the fk_seller key during a POST request.

Breaking Down the Solution

Identify the Error Source

In your original get_seller method, you have this line:

[[See Video to Reveal this Text or Code Snippet]]

Corrected Method

To fix this, we need to adjust the get_seller method. Instead of accessing the ID of the fk_user_id using .id, simply return the ID directly:

[[See Video to Reveal this Text or Code Snippet]]

Summary of Changes

Remove the call to .id on the ForeignKey field:

This change allows you to return the integer ID directly, avoiding the erroneous attempt to access the pk property.

Implementation in the POST Method

You should now be able to use the corrected get_seller when handling POST requests to set the fk_seller. Here is how the post method might look after incorporating the changes:

[[See Video to Reveal this Text or Code Snippet]]

By applying these changes, you should no longer see the AttributeError during your operations.

Conclusion

Errors like AttributeError: 'int' object has no attribute 'pk' can be quite frustrating, but with a clear understanding of how Django handles ForeignKey relationships and proper function implementation, you can easily resolve them. Always ensure you return the correct object type from your queries and handle foreign keys appropriately.

If you encounter similar issues or have further questions, feel free to reach out and share your experiences with Django development!