Sometimes, when using ActiveRecord, we need to know if some attribute value has changed after it was loaded from the database. To make things easier and avoid duplicated code, I created this behavior to help me with this task. Basically, what it does is to make a copy of all attributes values from the object, right after it is loaded from the database, so the behavior can work with this original values to know if any of them was changed.

Usage

The behavior usage is pretty simple. First, add the behavior to the ActiveRecord where you intend to use it:

<?php 
class User extends ActiveRecord {
	...
	public function behaviors() {
		return array(
			'AttributesBackupBehavior' => 'ext.AttributesBackupBehavior',
		);
	}
	...
}
?>

After this, 3 new methods will be added to your User class: attributesChanged(), attributeChanged() and getOldAttributeValue().

Below is a description of it:

attributesChanged()

With this method you can check if any of the object attributes was changed after it was loaded from the database:

<?php
$user = User::model()->find(); // User->status == 'Active'
var_dump($user->attributesChanged()); // FALSE
$user->status = 'Inactive';
var_dump($user->attributesChanged()); // TRUE
?>

attributeChanged()

This should be used when you want to know if a specific attribute value was changed:

<?php
$user = User::model()->find(); // User->status == 'Active'
$user->status = 'Inactive';
var_dump($user->attributeChanged('email')); // FALSE
var_dump($user->attributeChanged('status')); // TRUE
?>

getOldAttributeValue()

In case you need to retrieve the original value loaded from the database, this is the method you gonna use:

<?php
$user = User::model()->find(); // User->status == 'Active'
$user->status = 'Inactive';
var_dump($user->getOldAttributeValue('status')); // 'Active'
?>

Besides those three methods, there’s also one property that can be configured in this behavior: $reloadAfterSave.

By default, after you call the ActiveRecord save method, the old attributes will be erased and filled with the just saved new ones, show it will reflect the stored record. If for some reason you want to keep the original loaded values, you need to set $reloadAfterSave as false:

<?php 
class User extends ActiveRecord {
	...
	public function behaviors() {
		return array(
			'AttributesBackupBehavior' => array(
				'class' => 'ext.AttributesBackupBehavior',
				'reloadAfterSave' => false,
		);
	}
	...
}
?>

You can donwload the extension from its page at the Yii Framework site: http://www.yiiframework.com/extension/attributesbackupbehavior/

You can also fork the projet at Github: https://github.com/davialexandre/AttributesBackupBehavior