protected function dbUpdate($category, $key, $value)
    {
        $updated_by = \Yii::$app->user->getId();
        $this->getDb()->createCommand('
            UPDATE
                {{setting}}
            SET
                `value` = :value,
                `updated_at` = NOW(),
                `updated_by` = :updated_by
            WHERE
                category = :category
                AND `key` = :key
        ', compact('category', 'key', 'value', 'updated_by'))->execute();
    }