Скачать или смотреть How to Skip Records in discard_all Method with Discard Gem in Ruby on Rails

Discover how to use conditions with the discard gem in Ruby on Rails to selectively discard comments based on attributes.
---
This video is based on the question https://stackoverflow.com/q/63676838/ asked by the user 'sara lance' ( https://stackoverflow.com/u/13765315/ ) and on the answer https://stackoverflow.com/a/63705630/ provided by the user 'sara lance' ( https://stackoverflow.com/u/13765315/ ) 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: Skip record in discard_all method with discard gem

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.
---
How to Skip Records in discard_all Method with Discard Gem in Ruby on Rails

When working with Ruby on Rails, handling associations effectively while using gems like Discard can sometimes be challenging. One common scenario is when you need to remove associated records conditionally - for instance, discarding comments only if certain conditions are met. A user grappling with this concept recently posed a question: how can you skip records in the discard_all method when using the Discard gem? Let's delve into this issue and explore the solution.

Understanding the Scenario

In a typical Rails model, you might have something like this for a user that has many comments:

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

In the code above, when a user is discarded, all of their comments will also be discarded. However, what if you only want to discard comments that meet specific conditions? For example, you might want to skip the comments that have a certain attribute not set to nil. Fortunately, there's a straightforward way to achieve this.

The Solution: Using Conditions with discard_all

To selectively discard comments based on specific attributes, you can modify the after_discard and after_undiscard callbacks to include conditions. Here's how you can do this effectively:

Discard Comments Condition: Use a conditional statement in your after_discard method to target only those comments that meet your criteria. For example, you may want to discard comments only when their status is 0.

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

Undiscard Comments Condition: Similarly, in the after_undiscard method, you can specify which comments to undiscard. In this example, you might want to undiscard only those comments where deleted_by is nil.

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

Summary of the Code Changes

Your updated model would now look something like this:

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

Conclusion

With these simple adjustments, you can control which comments are discarded or undiscarded based on their attributes. This not only makes your application more robust but also adheres to better data management practices. If you're using the Discard gem in your Ruby on Rails application, remember that incorporating conditions into your discard_all methods can enhance functionality and provide greater flexibility in your application's behavior.

If you have further questions or need specific examples related to the Discard gem, feel free to reach out in the comments below!