mysqli에 대한 설명과 MySQLi 관련 레퍼런스 https://www.php.net/manual/en/mysqli.overview.php PHP: Overview - Manual mysqli can be great in some circumstances but much work has been put into PHP Portable Data Objects (PDO) which you should also consider when choosing a way to connect to your database using php. For example, PDO supports MySQL with minimal performance hit www.php.net https://www.php.net/manual..