Yii migration cache disable

gistfile1.txt

public function up()
{
    $this->addColumn('post', 'alias', 'varchar(255) NOT NULL');
 
    Yii::app()->cache->flush();
    Yii::app()->db->schema->getTables();
    Yii::app()->db->schema->refresh();
 
    foreach (Post::model()->findAll() as $post) {
        $post->save();
    }
}