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Adding explanation about how the callback chain is wrapped in a transaction

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CassioMarques
2009-01-11 20:35:14 -02:00
parent 8b63abbb08
commit de565b7e1d
2 changed files with 2 additions and 2 deletions
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railties/doc/guides/html/activerecord_validations_callbacks.html
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@@ -1262,7 +1262,7 @@ http://www.gnu.org/software/src-highlite -->
</div>
<h2 id="_halting_execution">12. Halting Execution</h2>
<div class="sectionbody">
<div class="paragraph"><p>As you start registering new callbacks for your models, they will be queued for execution. This queue will include all your model&#8217;s validations, the registered callbacks and the database operation to be executed. However, if at any moment one of the <tt>before_create</tt>, <tt>before_save</tt>, <tt>before_update</tt> or <tt>before_destroy</tt> callback methods returns a boolean <tt>false</tt> (not <tt>nil</tt>) value, this execution chain will be halted and the desired operation will not complete: your model will not get persisted in the database, or your records will not get deleted and so on.</p></div>
<div class="paragraph"><p>As you start registering new callbacks for your models, they will be queued for execution. This queue will include all your model&#8217;s validations, the registered callbacks and the database operation to be executed. However, if at any moment one of the <tt>before_create</tt>, <tt>before_save</tt>, <tt>before_update</tt> or <tt>before_destroy</tt> callback methods returns a boolean <tt>false</tt> (not <tt>nil</tt>) value or raise and exception, this execution chain will be halted and the desired operation will not complete: your model will not get persisted in the database, or your records will not get deleted and so on. It&#8217;s because the whole callback chain is wrapped in a transaction, so raising an exception or returning <tt>false</tt> fires a database ROLLBACK.</p></div>
</div>
<h2 id="_callback_classes">13. Callback classes</h2>
<div class="sectionbody">

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railties/doc/guides/source/activerecord_validations_callbacks.txt
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@@ -747,7 +747,7 @@ The +after_initialize+ and +after_find+ callbacks are a bit different from the o
== 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. However, if at any moment one of the +before_create+, +before_save+, +before_update+ or +before_destroy+ callback methods returns a boolean +false+ (not +nil+) value, this execution chain will be halted and the desired operation will not complete: your model will not get persisted in the database, or your records will not get deleted and so on.
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. However, if at any moment one of the +before_create+, +before_save+, +before_update+ or +before_destroy+ callback methods returns a boolean +false+ (not +nil+) value or raise and exception, this execution chain will be halted and the desired operation will not complete: your model will not get persisted in the database, or your records will not get deleted and so on. It's because the whole callback chain is wrapped in a transaction, so raising an exception or returning +false+ fires a database ROLLBACK.
== Callback classes