为什么我的PDO不起作用? [英] Why is my PDO not working?

问题描述

我开始使用PDO，并且已使用PDO成功连接到MySQL.但是，当我尝试从数据库中选择内容时，什么也没有发生.什么也没有回应. (即使我在该表中有记录，并且该列的用户名也存在)PHP日志中没有错误.

I am starting to use PDO and I successfully connected to MySQL using PDO. However, when I try to SELECT stuff from my DB, nothing happens. Nothing is echoed. (even though I have records in that table, and the column username exists) No error in my PHP log.

我正在使用MAMP，并且所有PDO组件似乎都在phpinfo()中工作(因为我一开始就可以连接到db)

I am using MAMP and all PDO components seem to be working in phpinfo() (since I was able to connect to db in the first place)

请让我知道可能出了什么问题.非常感谢

Please let me know what could have gone wrong. Thanks a lot

    <?php
    try 
    {
        $connection = new PDO('mysql:host=localhost;dbname:my_db','my_username',
                              'xxxxxxx');   


            $stmt=$connection->prepare("SELECT * FROM users");
            $stmt->execute();

            while ($row=$stmt->fetch(PDO::FETCH_OBJ)){

                echo $row->username;
            }

    }

    catch(Exception $e)
    {
        echo "There was an error connecting to the database";
    }

    ?>

推荐答案

您需要告诉PDO您希望它引发异常:

You need to tell PDO that you want it to throw exceptions:

$connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

在下面的评论中，很明显您的DSN不正确.应该是:

Following your comment below, it is apparent that your DSN is incorrect. It should be:

$connection = new PDO('mysql:host=localhost;dbname=my_db','my_username','xxxxxxx');

请注意，语法是dbname=，而不是dbname:(您最初使用的语法).

Note that the syntax is dbname= rather than dbname: (which you had originally).

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