MySQL连接功能不工作？

Question

我正在尝试连接到我的数据库，但它显示了mysql_connect函数中的错误。

错误是：致命错误：未捕获错误：调用C:\xampp\htdocs\connect中未定义的函数mysql\u connect（）。php:12堆栈跟踪：#0 C:\xampp\htdocs\Test。php（3）：在C:\xampp\htdocs\Connect中抛出require（）#1{main}。php在线12

连接文件：

<?php  

$db_host = "localhost"; 
// Place the username for the MySQL database here 
$db_username = "root";  
// Place the password for the MySQL database here 
$db_pass = "";  
// Place the name for the MySQL database here 
$db_name = "oscar"; 

// Run the connection here  
$con = mysql_connect("db_host","$db_username","$db_pass");
if (!$con)
{
  die('Could not connect: ' . mysql_error());
}
mysql_select_db("$db_name", $con);
try 
{
 $conn = new PDO("mysql:host=$db_host;dbname=$db_name", $db_username, $db_pass);
// set the PDO error mode to exception
 $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 echo "Connected successfully"; 
}
catch(PDOException $e)
{
 echo "Connection failed: " . $e->getMessage();
}

?>

文本文件：

<?php
// Connect to the MySQL database  
require "Connect.php"; 
echo "Success";
?>

Answer 1

php 5.5中不推荐使用mysql函数。0.我已更改了您代码中的一些更改。$符号已添加到mysqli connect语句中。

$con = mysqli_connect("$db_host","$db_username","$db_pass");
if (!$con)
{
  die('Could not connect: ' . mysqli_error());
}
mysqli_select_db("$db_name", $con);

Answer 2

函数mysql\u connect是一个不推荐使用的函数。相反，您应该使用mysqli\u connect在这里阅读更多关于此的信息

以下代码应该可以工作：

<?php
/**
 * Created by PhpStorm.
 * User: ...
 * Date: 5-12-2017
 * Time: 09:47
 * Database connection.
 */
?>
<?php
define('DB_SERVER', 'localhost');
define('DB_USERNAME', 'admin');
define('DB_PASSWORD', 'admin');
define('DB_DATABASE', 'your_database');
$db = mysqli_connect(DB_SERVER,DB_USERNAME,DB_PASSWORD,DB_DATABASE);

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

Answer 3

为什么你同时使用mysql_connect甚至PDO？mysql已被弃用，因此容易受到sql注入的影响。

只有此代码才能连接到数据库

<?php
$db_host = "localhost";
// Place the username for the MySQL database here
$db_username = "root";
// Place the password for the MySQL database here
$db_pass = "";
// Place the name for the MySQL database here
$db_name = "oscar";


try {
    $conn = new PDO("mysql:host=$db_host;dbname=$db_name", $db_username, $db_pass);
// set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "Connected successfully";
} catch (PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}