Almost every model representing content should have creation and modification dates to show the content actuality, revisions, and so on. In Yii there are two good ways to automate this, which are as follows:
- Overriding
beforeValidate - Using the
CTimestampBehaviorbehavior from Zii
We will see how to apply these to blog posts. We will use Unix timestamps to store the date and time.
- Create a new application by using
yiic webappas described in the official guide at the following URL:http://www.yiiframework.com/doc/guide/en/quickstart.first-app
- Set up a database connection and create a table named
postas follows:DROP TABLE IF EXISTS `post`; CREATE TABLE IF NOT EXISTS `post` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `title` VARCHAR(255) NOT NULL, `text` TEXT NOT NULL, `created_on` INT(10) UNSIGNED NOT NULL, `modified_on` INT(10) UNSIGNED NOT NULL, PRIMARY KEY (`id`) );
- Generate a
Postmodel using Gii. - Remove everything about
created_onandmodified_onfrom therulesmethod of the model.
- We will start with overriding the
beforeValidatemethod. Openprotected/models/Post.phpand add the following method:protected function beforeValidate() { if($this->getIsNewRecord()) $this->created_on = time(); $this->modified_on = time(); return parent::beforeValidate();; } - Now add the following code to the new controller and run it:
$post = new Post(); $post->title = "test title"; $post->text = "test text"; $post->save(); echo date('r', $post->created_on); - You should get a date and time. Since we have simply created a post, it will be the current date and time. Another method is to use
CTimestampBehavior. Delete thePostmodel and generate it one more time by using Gii. Remove everything aboutcreated_onandmodified_onfrom therulesmethod of the model. Add the following method to the model:public function behaviors() { return array( 'timestamps' => array( 'class' => 'zii.behaviors.CTimestampBehavior', 'createAttribute' => 'created_on', 'updateAttribute' => 'modified_on', 'setUpdateOnCreate' => true, ), ); }
The beforeValidate method executes just before the model validation starts. In this method, modified_on is always filled and created_on is filled only if the model is new, which is only when we are creating a post.
When we use the ready behavior from Zii, we specify createAttribute and updateAttribute to match the field names we have chosen. The setUpdateOnCreate property triggers filling modified_on when a record is inserted. The rest is done by the behavior function.
In order to learn more about CTimestampBehavior, refer to the following API page: