Attribute::changeType PHP Method

    public function changeType($currentType, $newType)
    {
        if ($currentType == $newType) {
            return true;
        }
        $value = new AttributeValue();
        $currentCol = $value->column($currentType);
        $newCol = $value->column($newType);
        if ($currentCol == $newCol) {
            return true;
        }
        $transaction = Yii::app()->getDb()->beginTransaction();
        try {
            Yii::app()->getDb()->createCommand(sprintf('UPDATE {{store_product_attribute_value}} SET %s = %s WHERE attribute_id = :id', $newCol, $currentCol))->bindValue(':id', $this->id)->execute();
            Yii::app()->getDb()->createCommand(sprintf('UPDATE {{store_product_attribute_value}} SET %s = null WHERE attribute_id = :id', $currentCol))->bindValue(':id', $this->id)->execute();
            $transaction->commit();
            return true;
        } catch (Exception $e) {
            $transaction->rollback();
            return false;
        }
    }