$pdo = new PDO("This is the parameter","root","root");
I have seen "host", "dbname", "port", "charset"
But some people's tutorials only have "host" and "dbname", so I want to ask him how many
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
