如何登入伺服器？

<?php
$db_name = "資料表名稱";
$mysql_username = "root";
$mysql_password = "密碼";
$server_name = "127.0.0.1";
$conn = mysqli_connect($server_name,$mysql_username,$mysql_password,$db_name);
mysqli_set_charset($conn, "UTF8");//中文化
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
//網頁專用，加於head中間。
if($conn){
//echo"connect success";
}
else{echo"connect not success";}

?>