1、
class mysql{
__construct([string hjost [,string username[,string password[, string dbname
[,int port[,string socket]]]]]]])
}
2、
$mysqli = new mysqli("localhost","mysql_user","mysql_password","dbname");
3、
<?php
//创建mysqli对象
$mysqli = new mysqli();
//连接指定的MySQL数据库服务器
$mysqli->connect("localhost","mysql_user","mysql_password");
//选择特定的数据库
$mysqli->select_db("dbname");
?>