適應php代碼使用mysqli而不是mysql

Question

我有代碼可以使用PHP5.6，但不能使用PHP7.0。這很短，所以我認爲我可以在沒有問題的情況下進行修改，但我錯了。原始腳本在下面，接着我嘗試使用mysqli。有人請告訴我我需要做些什麼才能做到正確嗎？

OLD CODE

<?php 
$db_host = "localhost"; 
$db_name = "database_name"; 
$db_user = "user_name"; 
$db_pass = "pass"; 

$link = mysql_connect($db_host, $db_user, $db_pass) or die("Could not connect to database as ".$db_user."@".$db_host."!"); 
mysql_select_db($db_name) or die("Could not select database ".$db_name); 
?> 

新規範

<?php 
$db_host = "localhost"; 
$db_name = "database_name"; 
$db_user = "user_name"; 
$db_pass = "pass"; 

$link = new mysqli_connect($db_host,$db_user,$db_pass) or die('Unable to establish a DB connection'); 
mysqli_select_db($db_name) or die("Could not select database ".$db_name); 
?> 

Answer 1

在mysqli_select_db添加$link，請參閱here瞭解更多信息

mysqli_select_db($link, $db_name)