Resolving the order_by Issue in Django's ListView скачать в хорошем качестве

Resolving the order_by Issue in Django's ListView

Learn how to fix the issue of `get_queryset` ignoring your custom ordering in Django's ListView. This guide breaks down the solution in an easy-to-understand format. --- This video is based on the question https://stackoverflow.com/q/68325723/ asked by the user 'oscurodrago' ( https://stackoverflow.com/u/721253/ ) and on the answer https://stackoverflow.com/a/68325761/ provided by the user 'willeM_ Van Onsem' ( https://stackoverflow.com/u/67579/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Django ListView ignore Order_by in get_Queryset Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Resolving the order_by Issue in Django's ListView When working with Django's ListView, you might encounter a situation where your custom ordering specified in the get_queryset() method is ignored, leading to results sorted by the default order defined in the model's Meta class. If you've found yourself in this predicament, don't worry. In this post, we will dissect the problem and provide a clear solution to ensure that your order_by clause works as intended. Understanding the Problem In Django, when you override the get_queryset() method in a ListView, it is responsible for fetching and returning the data that will be displayed in your view. However, if not handled correctly, Django may revert to the default ordering defined in the model’s Meta class. This is likely caused by the way you handle the queryset within your get_queryset() method. Example Scenario Consider the following view where the aim is to order entries of a Tag model by slug, tag, and date. However, the output reflects the default order: [[See Video to Reveal this Text or Code Snippet]] Instead of the expected: [[See Video to Reveal this Text or Code Snippet]] The Solution To ensure that your specified order is respected, you need to explicitly assign the ordered queryset back to the queryset variable. Below is a refined version of the original get_queryset(): Modified ListView Code [[See Video to Reveal this Text or Code Snippet]] Key Takeaways Immutable QuerySets: In Django, QuerySets are immutable. This means that any modification to a QuerySet does not change the original but returns a new modified QuerySet. Therefore, it’s crucial to assign the ordered QuerySet back to the variable. Filtering: The if statements for filtering the queryset based on URL parameters (like category or search) need to be intact as they will retain the order you applied. Testing: Always test your changes by logging the generated query to ensure that the order_by clause is applied correctly. By following these practices, you can gain control over the ordering of your entries in Django's ListViews and ensure the data is displayed exactly as you intend. Conclusion In summary, issues with order_by in Django's ListView can often be resolved with a few simple adjustments. By understanding the behavior of QuerySets and ensuring your ordering statement is re-assigned properly, you can sidestep the confusion of default model ordering. Happy coding!