Insert Update Delete with createCommand in yii

public function assignVehicle($driver_id=null,$vehicle_id=null)
{
$sql = "UPDATE `drivers` SET `vehical_id`=$vehicle_id WHERE id=:driver_id";

$parameters = array(":driver_id"=>$driver_id);

Yii::app()->db->createCommand($sql)->execute($parameters);
}

public function insertCharges($area_id=null,$charge=null){


$sql = "insert into delivery_charge (`area_id`,`charge`) values (:area_id,:charge)";

$parameters = array(":area_id"=>$area_id,":charge"=>$charge);

Yii::app()->db->createCommand($sql)->execute($parameters);


}

$sql = "delete from `AuthItemChild` where parent=:parent AND child=:child";

  $parameters = array(":parent"=>$parent,":child"=>$child);


  Yii::app()->db->createCommand($sql)->execute($parameters);