Struktur kode Transaksi PHP PDO MySQL

Beberapa catatan umum:Jangan gunakan bindParam() kecuali jika Anda menggunakan prosedur yang mengubah nilai parameter Oleh karena itu, use bindValue() . bindParam() menerima nilai argumen sebagai variabel yang direferensikan. Itu berarti Anda tidak dapat melakukan $stmt->bindParam(':num', 1, PDO::PARAM_INT); - menimbulkan error. Selain itu, PDO memiliki fungsi sendiri untuk mengontrol transaksi, Anda tidak perlu mengeksekusi query secara manual.

Saya menulis ulang kode Anda sedikit untuk menjelaskan bagaimana PDO dapat digunakan:

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
    }    
}