public static function sql_prepare($str, $used_in_like = false)
    {
        if (!self::getInstance()->pdo_db) {
            self::getInstance()->connect();
        }

        if (is_array($str)) {
            foreach ($str as &$v) {
                $v = self::sql_prepare($v);
            }
        } else {
            $str = substr(self::getInstance()->pdo_db->quote(trim((string)$str)), 1, -1);

            if ($used_in_like) {
                $str = str_replace(['_', '%'], ['\_', '\%'], $str);
            }
        }

        return $str;
    }