php - mysql连接失败

Question

我正在使用这段代码连接mysql

    $con = mysql_connect("localhost", "username" , "password");
    if (!$con)
    {
       die('Could not connect: ');
    }
    else 
     { echo "connection failed....";}
   mysql_select_db("ManagersDatabase", $con);

mysql 数据库位于/var/lib/mysql/ManagersDatabase。我的 php 页面位于 /var/www/html/ 中。它不打印任何东西。我的代码有什么问题？

Answer 1

这是您应该使用 PDO 进行连接的方式:and utilizing prepared query's when querying.

<?php 
try{
    $con = new PDO('mysql:host=127.0.0.1;dbname=your_database','root','password');
    $con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $con->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
    $con->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE,PDO::FETCH_ASSOC);
}catch (Exception $e){
    die('Cannot connect to database. Details:'.$e->getMessage());
}
?>

或者mysqli and utilizing prepared query's when querying .

<?php
$con = new mysqli("127.0.0.1", "user", "password", "your_database");
if ($con->connect_errno) {
    die("Failed to connect to MySQL: (".$con->connect_errno.") ".$con->connect_error);
}
print_r($con);
?>

编辑(回复评论):如果添加 print_r($con);，您应该会看到 mysqli 连接对象，如下所示:

/*
mysqli Object
(
    [affected_rows] => 0
    [client_info] => mysqlnd 5.0.10 - 20111026 - $Id: b0b3b15c693b7f6aeb3aa66b646fee339f175e39 $
    [client_version] => 50010
    [connect_errno] => 0
    [connect_error] => 
    [errno] => 0
    [error] => 
    [error_list] => Array
        (
        )

    [field_count] => 0
    [host_info] => 127.0.0.1 via TCP/IP
    [info] => 
    [insert_id] => 0
    [server_info] => 5.5.25a
    [server_version] => 50525
    [stat] => Uptime: 10  Threads: 1  Questions: 1  Slow queries: 0  Opens: 33  Flush tables: 1  Open tables: 26  Queries per second avg: 0.100
    [sqlstate] => 00000
    [protocol_version] => 10
    [thread_id] => 1
    [warning_count] => 0
)
*/

其他方法已经过时，很快就会(谢天谢地)被弃用。