Functions
function update($table, $columns, $conditions='', $params=array())
Sample
The update() method builds and executes an UPDATE SQL statement.
<?php $user=Yii::app()->db->createCommand() ->update('tbl_user', array( 'username'=>'bsourcecode', ), 'user_id=:id', array(':id'=>1)); ?>
OUTPUT SQL
UPDATE `tbl_user` SET `username`=:username WHERE user_id=:id