Скачать или смотреть Autofilling job_time_estimation in Django Forms

Discover how to automatically set the `job_time_estimation` field in a Django model form using data from associated objects with a many-to-many relationship.
---
This video is based on the question https://stackoverflow.com/q/67971417/ asked by the user 'Arnas' ( https://stackoverflow.com/u/14959018/ ) and on the answer https://stackoverflow.com/a/67971765/ provided by the user 'arjun' ( https://stackoverflow.com/u/12061653/ ) 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: Autofilling Django model form field with data from associated objects

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.
---
Autofilling job_time_estimation in Django Forms: A Step-by-Step Guide

If you're working with Django and struggling to autofill a form field from associated objects, you’ve come to the right place. Specifically, we will tackle how to fill a job_time_estimation field in a form by summing up the service_stats_estimate_duration values from related objects. This guide will take you through both the problem and the solution, ensuring that your form works effectively.

The Problem

You have a model form that allows users to create new job entries. Upon submitting this form, you want an "invisible" field called job_time_estimation to be automatically calculated by summing the service_stats_estimate_duration values from selected ServiceItemStats objects linked to the JobEntry model.

For example, if you select two ServiceItemStats entries that have estimates of 60 and 90, your form should save a total value of 150 in the job_time_estimation attribute of the created JobEntry object.

However, you might run into an issue if you're not structuring your save method correctly. As stated in your error message ("name 'serviceItemStats' is not defined"), it indicates that there is a problem with how you are accessing the related model data during the form submission process.

The Solution

Let’s break down how to autofill the job_time_estimation field step by step.

Step 1: Update the Model’s Save Method

You will need to sum the values after the object is created. You can use Django's aggregate function for this. Modify your save method in the JobEntry model as follows:

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

Step 2: Update the Form

Your form code doesn’t require changes as it is correctly set to include serviceItemStats. Just ensure it properly allows for multiple selections:

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

Step 3: Update the View

Finally, update the form_valid method in your view. Here’s an example:

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

Conclusion

By following these steps, you will successfully autofill the job_time_estimation in your Django application by calculating the total duration of the selected ServiceItemStats objects linked to your new JobEntry. This method ensures that the calculations happen seamlessly during form submission without any errors.

If you encounter any issues or need further clarification, feel free to ask questions or seek assistance from the Django community. Happy coding!