diff options
Diffstat (limited to 'guides/source/active_record_callbacks.md')
| -rw-r--r-- | guides/source/active_record_callbacks.md | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/guides/source/active_record_callbacks.md b/guides/source/active_record_callbacks.md index 77bd3c97e8..b1705855d0 100644 --- a/guides/source/active_record_callbacks.md +++ b/guides/source/active_record_callbacks.md @@ -117,6 +117,10 @@ Here is a list with all the available Active Record callbacks, listed in the sam WARNING. `after_save` runs both on create and update, but always _after_ the more specific callbacks `after_create` and `after_update`, no matter the order in which the macro calls were executed. +NOTE: `before_destroy` callbacks should be placed before `dependent: :destroy` +associations (or use the `prepend: true` option), to ensure they execute before +the records are deleted by `dependent: :destroy`. + ### `after_initialize` and `after_find` The `after_initialize` callback will be called whenever an Active Record object is instantiated, either by directly using `new` or when a record is loaded from the database. It can be useful to avoid the need to directly override your Active Record `initialize` method. @@ -254,7 +258,11 @@ Halting Execution As you start registering new callbacks for your models, they will be queued for execution. This queue will include all your model's validations, the registered callbacks, and the database operation to be executed. -The whole callback chain is wrapped in a transaction. If any _before_ callback method returns exactly `false` or raises an exception, the execution chain gets halted and a ROLLBACK is issued; _after_ callbacks can only accomplish that by raising an exception. +The whole callback chain is wrapped in a transaction. If any callback raises an exception, the execution chain gets halted and a ROLLBACK is issued. To intentionally stop a chain use: + +```ruby +throw :abort +``` WARNING. Any exception that is not `ActiveRecord::Rollback` or `ActiveRecord::RecordInvalid` will be re-raised by Rails after the callback chain is halted. Raising an exception other than `ActiveRecord::Rollback` or `ActiveRecord::RecordInvalid` may break code that does not expect methods like `save` and `update_attributes` (which normally try to return `true` or `false`) to raise an exception. |