protected function _fieldName($field) {
		$regex = '/^[a-z0-9_-]+\.[a-z0-9_-]+$/iS';

		if (strpos($field, '.') !== false && preg_match($regex, $field)) {
			list($first, $second) = explode('.', $field, 2);
			return $second;
		}
		return $field;
	}