How to Solve Django ValueError: Field 'id' expected a number Error

Discover how to resolve the `ValueError` in Django when filtering by user ID and ensure your code runs without interruptions.
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How to Solve Django ValueError: Field 'id' expected a number Error

When working with Django applications, developers often run into various types of errors. One frustrating issue that many encounter is the ValueError: Field 'id' expected a number. This error typically occurs during a database filtering process when a string value is mistakenly passed where a numerical value is expected. In this post, we will break down a common scenario that triggers this error in a Django project and explore a solution to fix it.

The Problem

Consider that you're building a Django web application where users can filter completed work records based on various criteria, including the worker's name. However, despite having logic set up for filtering, you may encounter the following error when attempting to filter on a worker's name:

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

This error signifies that the application is trying to filter by a string (the worker's name) instead of the worker's corresponding ID (which is a number). This mismatch between the expected and provided data types leads to the ValueError.

Understanding the Code

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

Here, worker is a string containing the worker's name. However, the worker field in the CompletedWork model expects a user ID, which is where the error originates.

The Solution

To resolve this issue, we need to modify the logic that retrieves the worker ID based on the provided name. Instead of directly filtering with the worker, we will first look up the appropriate CustomUser instance based on the provided name and then use its ID for the filter.

Step-by-Step Implementation

Extract and Validate the Worker Name: Adjust the code to extract the worker's name from the request and validate it.

Retrieve Worker ID: Use Django’s ORM to look up the user by their name.

Here is how you can implement this change:

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

Explanation of the Code Changes

We start by retrieving the worker parameter from the request.

We then try to separate the worker's name into last name, first name, and possibly a middle name.

Finally, if we successfully extract a CustomUser object, we can filter our queryset with its corresponding ID.

Conclusion

By adjusting the logic to find the user's ID based on their name, you can effectively avoid the ValueError when filtering records in Django. This solution not only helps in resolving the immediate error but also makes your code more robust and easier to maintain.

If you continue to run into issues with your Django application, don't hesitate to check your data types and ensure you're passing the values expected by Django's ORM. Happy coding!