PHP怎么处理数据库连接池与数据获取

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

try {
    $pdo = new PDO($dsn, $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch (PDOException $e) {
    echo 'Connection failed: ' . $e->getMessage();
}

$stmt = $pdo->query('SELECT * FROM users');
while ($row = $stmt->fetch()) {
    echo $row['name'] . ' ' . $row['email'] . '<br>';
}

// Create a pool of PDO connections
$pdoPool = new SplObjectStorage();

// Create multiple PDO connections and add them to the pool
for ($i = 0; $i < 10; $i++) {
    $pdo = new PDO($dsn, $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $pdoPool->attach($pdo);
}

// Get a connection from the pool
$pdo = $pdoPool->current();
$pdoPool->next();

// Use the connection to query data
$stmt = $pdo->query('SELECT * FROM users');
while ($row = $stmt->fetch()) {
    echo $row['name'] . ' ' . $row['email'] . '<br>';
}

// Return the connection to the pool
$pdoPool->rewind();
$pdoPool->attach($pdo);