PDO Query Fails Silently: How Do I Get PDO Error Messages?

Frequently Asked Questions About PDO: PDO Query Failures and Error Handling

PDO (PHP Data Objects) offers a standardized interface for interacting with different database systems. However, some of its features can be unfamiliar to PHP developers, leading to common questions regarding prepared statements and error handling. This article addresses one of these frequently asked questions:

PDO Query Fails but I Can't See Any Errors. How to Get an Error Message from PDO?

To resolve this issue, it is essential to enable PDO's exception handling. By default, PDO handles errors as regular PHP errors, which may not be visible. To handle errors as exceptions, set the PDO ERRMODE attribute to PDO::ERRMODE_EXCEPTION when establishing a connection. This allows PDO to throw exceptions on database errors, making them available for error handling.

Here is an example of setting up a PDO connection with exception handling:

$dsn = "mysql:host=$host;dbname=$db;charset=utf8";
$opt = array(
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    // other options
);
$pdo = new PDO($dsn, $user, $pass, $opt);

With this setting, all database errors will be thrown as exceptions. These exceptions can be caught using try..catch blocks or a dedicated error handler. Uncaught exceptions will act as regular PHP errors, following site-wide error reporting settings.

It is important to ensure that PHP errors are visible. On production servers, it is recommended to log errors instead of displaying them on the screen. This can be achieved by setting:

error_reporting(E_ALL);
ini_set('display_errors', 0);
ini_set('log_errors', 1);

On development servers, it may be more convenient to display errors on the screen:

error_reporting(E_ALL);
ini_set('display_errors', 1);

Always avoid using the error suppression operator (@) before PDO statements, as this can hide important error information.

The above is the detailed content of PDO Query Fails Silently: How Do I Get PDO Error Messages?. For more information, please follow other related articles on the PHP Chinese website!