$pdo->exec($sql);Why does it always return false?

Question

$pdo = new PDO($dsn,$username,$password);

var_dump($pdo);//The output is object(PDO)#1 (0) { }

//Execute the insert statement

$sql = "update text set age=age 1 where id=5";

$records = $pdo ->exec($sql);

var_dump($records);