从 MySQL 更改为 MySQLi，不再工作

Question

在将 mysql 更改为 mysqli 时，我从一个完全正常工作的 php 文件变成了一个不存在的文件！我按照说明进行了每项更改，您能帮忙吗？这是我之前（mysql）和之后（mysqli）的代码：

之前（mysql）：

<?php

function db_open() {
    $dtbhost=":/something/home/something2/mysql/run/mysql.sock";
    $dtbuser="root";
    $dtbpass="mypass";
    $dtbname="mydb";
    $connection   =   mysql_connect("$dtbhost",   "$dtbuser",   "$dtbpass") 
        or die('00: No Connection');
    @ mysql_select_db("$dtbname") or die('01: No Database');      
}

session_start(); // Starting Session
$error=''; // Variable To Store Error Message
if (isset($_POST['submit'])) {
    if (empty($_POST['username']) || empty($_POST['password'])) {
        echo ("<SCRIPT LANGUAGE='JavaScript'> 
            window.alert('You did not complete all of the required fields') 
            window.location.href='index.html' 
            </SCRIPT>");
    }
    else
    {
    // Define $username and $password
    $username=$_POST['username'];
    $password=$_POST['password'];
    // Establishing Connection with Server by passing server_name, user_id and password as a parameter
    db_open(); 
    // To protect MySQL injection for Security purpose
    $username = stripslashes($username);
    $password = stripslashes($password);
    $username = mysql_real_escape_string($username);
    $password = mysql_real_escape_string($password);
    $query = mysql_query("SELECT * FROM login_users WHERE username = '$username' AND password = '$password'") 
            or die(mysql_error());

    $rows = mysql_num_rows($query);
    if ($rows == 1) {
        $_SESSION['login_user']=$username; // Initializing Session
        header("location: profile.html"); // Redirecting To Other Page

    } else {
        echo ("<SCRIPT LANGUAGE='JavaScript'> 
            window.alert('Wrong username password combination. Please re-enter.') 
            window.location.href='index.html' 
            </SCRIPT>");
    }
    mysql_close($connection); // Closing Connection
    }
}
?>

之后（mysqli）：

<?php

function db_open() {
    $dtbhost=":/something/home/something2/mysql/run/mysql.sock";
    $dtbuser="root";
    $dtbpass="mypass";
    $dtbname="mydb";
    $con = mysqli_connect("$dtbhost","$dtbuser","$dtbpass","$dtbname");

    // Check connection
    if (mysqli_connect_errno())
      {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
      }
}

session_start(); // Starting Session
$error=''; // Variable To Store Error Message
if (isset($_POST['submit'])) {
    if (empty($_POST['username']) || empty($_POST['password'])) {
        echo ("<SCRIPT LANGUAGE='JavaScript'> 
            window.alert('You did not complete all of the required fields') 
            window.location.href='index.html' 
            </SCRIPT>");
    }
    else
    {
    // Define $username and $password
    $username=$_POST['username'];
    $password=$_POST['password'];
    // Establishing Connection with Server by passing server_name, user_id and password as a parameter
    db_open(); 
    // To protect MySQL injection for Security purpose
    $username = stripslashes($username);
    $password = stripslashes($password);
    $username = mysqli_real_escape_string($con, $username);
    $password = mysqli_real_escape_string($con, $password);

    $query = mysqli_query($con, "SELECT * FROM login_users WHERE username = '$username' AND password = '$password'") 
            or die(mysqli_error());

    $rows = mysqli_num_rows($query);
    if ($rows == 1) {
        $_SESSION['login_user']=$username; // Initializing Session
        header("location: profile.html"); // Redirecting To Other Page

    } else {
        echo ("<SCRIPT LANGUAGE='JavaScript'> 
            window.alert('Wrong username password combination. Please re-enter.') 
            window.location.href='index.html' 
            </SCRIPT>");
    }
    mysqli_close($con); // Closing Connection
    }
}
?>

我得到的错误是：

警告：mysqli_connect(): php_network_getaddresses: getaddrinfo failed: hostname or servname provided, or not known in /something/home/something2/public_html/login.php on line 8

警告：mysqli_connect(): (HY000/2002): php_network_getaddresses: getaddrinfo 失败：提供主机名或服务名，或在 /something/home/something2/public_html/login.php 在第 8 行未能 连接到 MySQL：php_network_getaddresses：getaddrinfo 失败： 提供主机名或服务名，或未知

（第 8 行是：$con = mysqli_connect("$dtbhost","$dtbuser","$dtbpass","$dtbname");）

这会触发更多错误，因为 $con 为空。 任何帮助将不胜感激，谢谢！

Answer 1

$dtbhost 变量应该是 IP 地址或域名。例如：'localhost'、'127.0.0.1'、'example.com'等。不是套接字文件。