PHP PDO Database Connection Guide

To connect to a database using PDO in PHP, you first need to install the PDO extension. Then, you can follow the steps below to connect to the database using PDO.

1. Create a PDO object.

$dsn = 'mysql:host=localhost;dbname=mydatabase';
$username = 'username';
$password = 'password';

try {
    $pdo = new PDO($dsn, $username, $password);
    // 设置PDO错误模式为异常
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
    echo '数据库连接失败：' . $e->getMessage();
}

1. Perform database query.

try {
    $stmt = $pdo->query('SELECT * FROM users');
    
    // 获取查询结果
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
        echo $row['username'] . '<br>';
    }
} catch (PDOException $e) {
    echo '查询失败：' . $e->getMessage();
}

1. Execute the query using preprocessing statements.

try {
    $stmt = $pdo->prepare('SELECT * FROM users WHERE id = :id');
    $stmt->execute(['id' => 1]);
    
    // 获取查询结果
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
        echo $row['username'] . '<br>';
    }
} catch (PDOException $e) {
    echo '查询失败：' . $e->getMessage();
}

The code above connects to a MySQL database using a PDO object and performs some simple query operations. It can be used to perform operations such as adding, deleting, modifying, and searching based on specific needs.