PHP PDO MySQL 事务代码结构

Question

我正在尝试使用 PHP/PDO 在 MySQL 中设置我的第一个事务...

我有一个简单的问题，确定上一个查询是否成功的最佳方法是什么？这是我现在拥有的，但我更愿意找到一种使用 if 语句测试查询的方法。

这几乎是模拟代码，试图获得一个工作模型。我知道 $results 不能有效地测试任何东西是好是坏。我在那里更多地作为真正交易的占位符时间到了..

if ($_POST['groupID'] && is_numeric($_POST['groupID'])) {
    $sql = "SET AUTOCOMMIT=0";
    $dbs = $dbo->prepare($sql);
    $dbs->execute();

    $sql = "START TRANSACTION";
    $dbs = $dbo->prepare($sql);
    $dbs->execute();

    $sql = "DELETE FROM users_priveleges WHERE GroupID=:groupID";
    $dbs = $dbo->prepare($sql);
    $dbs->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
    $dbs->execute();

    try {
        $sql = "DELETE FROM groups WHERE GroupID=:groupID LIMIT 1";
        $dbs = $dbo->prepare($sql);
        $dbs->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
        $dbs->execute();

        $results["error"] = null;
        $results["success"] = true;

        try {
            $sql = "DELETE FROM users WHERE Group=:groupID";
            $dbs = $dbo->prepare($sql);
            $dbs->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
            $dbs->execute();

            $results["error"] = null;
            $results["success"] = true;

            $sql = "COMMIT";
            $dbs = $dbo->prepare($sql);
            $dbs->execute();
        }
        catch (PDOException $e) {
            $sql = "ROLLBACK";
            $dbs = $dbo->prepare($sql);
            $dbs->execute();

            $results["error"] = "Could not delete associated users! $e";
            $results["success"] = false;
        }   
    }
    catch (PDOException $e)
    {
        $sql = "ROLLBACK";
        $dbs = $dbo->prepare($sql);
        $dbs->execute();

        $results["error"] = "COULD NOT REMOVE GROUP! $e";
        $results["success"] = false;
    }
}

Answer 1

一些一般注意事项:不要使用 bindParam() 除非您使用修改参数值的过程因此，使用 bindValue()。 bindParam() 接受参数值作为引用变量。这意味着您不能执行 $stmt->bindParam(':num', 1, PDO::PARAM_INT); - 它会引发错误。此外，PDO 有自己的功能来控制事务，您不需要手动执行查询。

我稍微重写了您的代码以阐明如何使用 PDO:

if($_POST['groupID'] && is_numeric($_POST['groupID']))
{
    // List the SQL strings that you want to use
    $sql['privileges']  = "DELETE FROM users_priveleges WHERE GroupID=:groupID";
    $sql['groups']      = "DELETE FROM groups WHERE GroupID=:groupID"; // You don't need LIMIT 1, GroupID should be unique (primary) so it's controlled by the DB
    $sql['users']       = "DELETE FROM users WHERE Group=:groupID";

    // Start the transaction. PDO turns autocommit mode off depending on the driver, you don't need to implicitly say you want it off
    $pdo->beginTransaction();

    try
    {
        // Prepare the statements
        foreach($sql as $stmt_name => &$sql_command)
        {
            $stmt[$stmt_name] = $pdo->prepare($sql_command);
        }

        // Delete the privileges
        $stmt['privileges']->bindValue(':groupID', $_POST['groupID'], PDO::PARAM_INT);
        $stmt['privileges']->execute();

        // Delete the group
        $stmt['groups']->bindValue(":groupID", $_POST['groupID'], PDO::PARAM_INT);
        $stmt['groups']->execute();

        // Delete the user 
        $stmt['users']->bindParam(":groupID", $_POST['groupID'], PDO::PARAM_INT);
        $stmt['users']->execute();

        $pdo->commit();     
    }
    catch(PDOException $e)
    {
        $pdo->rollBack();

        // Report errors
    }    
}