Detailed Error Inspection with errorInfo()

The errorInfo() method returns an array containing detailed information about the last operation performed on the database or statement object. The array contains three elements: the standard SQLSTATE code (index 0), the driver-specific error code (index 1), and the driver-specific error message string (index 2). This is the most powerful tool for determining exactly why a query failed.

EXAMPLE

<?php
class Database {
    private $server = "localhost";
    private $username = "root";
    private $password = "";
    private $db_name = "pdo_db";
    public $connection;

    public function __construct() {
        try {
            // Added charset=utf8mb4 for character support
            $dsn = "mysql:host=" . $this->server . ";dbname=" . $this->db_name . ";charset=utf8mb4";
            $this->connection = new PDO($dsn, $this->username, $this->password);
            $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT);
        } catch(PDOException $e) {
            die("Connection failed: " . $e->getMessage());
        }
    }

    public function getErrorDetails() {
        // Intentionally incorrect query (column does_not_exist)
        $this->connection->query("SELECT does_not_exist FROM users");
        
        // Retrieve the array with details
        return $this->connection->errorInfo();
    }
}

// PART 3: Usage
$db = new Database();
$error = $db->getErrorDetails();

if ($error[0] !== "00000") {
    echo "Error message: " . $error[2];
} else {
    echo "Query succeeded without errors.";
}
?>

RESULT

The result will be displayed here...

Practical Application: We use the errorInfo method during development to quickly read the message returned to us by MySQL (e.g., "Unknown column in field list"). Check the process at home by following these steps:

Start the Apache and MySQL modules in the XAMPP control panel.
Ensure via phpMyAdmin that the users table exists within the pdo_db database.
The method returns an array; if there was no error, the array only contains the success code.
Insert the example below into your PHP file and intentionally misspell a column name.