php - 有交易时如何处理错误？

Question

这是我的代码:

try {
    $dbh_con->beginTransaction();

        $stmt1 = $dbh_conn->prepare("UPDATE activate_account_num SET num = num + 1");
        $stmt1->execute();

        $stmt2 = $dbh_con->prepare("SELECT user_id FROM activate_account WHERE token = ?");
        $stmt2->execute(array($token));
        $num_rows = $stmt2->fetch(PDO::FETCH_ASSOC);

        if ( $num_rows['user_id'] ){
            $_SESSION['error'] = 'all fine';

        } else {
            $_SESSION['error'] = 'token is invalid';
        }

    $dbh_con->commit();

    header('Location: /b.php');
    exit();

} catch(PDOException $e) {

    $dbh_con->rollBack();

    $_SESSION['error'] = 'something is wrong';
    header('Location: /b.php');
    exit();
}

如您所见，我的脚本会在出现异常时回滚所有查询。但当 if ( $num_rows['user_id'] ){ 为 false 时，它不会回滚。那么当条件为 false 时，我如何才能回滚查询并保留错误 'token is invalid' 呢？

Answer 1

只需抛出一个异常并像您已经做的那样捕获它。但不是一个 catch 语句而是两个:

try {
    $dbh_con->beginTransaction();

        $stmt1 = $dbh_conn->prepare("UPDATE activate_account_num SET num = num + 1");
        $stmt1->execute();

        $stmt2 = $dbh_con->prepare("SELECT user_id FROM activate_account WHERE token = ?");
        $stmt2->execute(array($token));
        $num_rows = $stmt2->fetch(PDO::FETCH_ASSOC);

        if ( $num_rows['user_id'] ){
            $_SESSION['error'] = 'all fine';

        } else {
            throw new \Exception('token is invalid');
        }

    $dbh_con->commit();

    header('Location: /b.php');
    exit();

} catch(PDOException $e) {

$dbh_con->rollBack();

$_SESSION['error'] = 'something is wrong';
header('Location: /b.php');
exit();
} catch(Exception $e) {

    $dbh_con->rollBack();

    $_SESSION['error'] = 'token is invalid';
    header('Location: /b.php');
    exit();
}