IDbTransaction.Rollback Metodo

Definizione

Spazio dei nomi:

System.Data

Assembly:

System.Data.Common.dll

Esegue il rollback di una transazione da uno stato in sospeso.

public:
 void Rollback();

public void Rollback ();

abstract member Rollback : unit -> unit

Public Sub Rollback ()

Eccezioni

Exception

Si è verificato un errore durante il tentativo di eseguire il commit della transazione.

InvalidOperationException

È già stato eseguito il rollback o il commit della transazione.

-oppure-

La connessione non funziona.

Esempio

Nell'esempio seguente vengono create istanze delle classi SqlConnection derivate e un oggetto SqlTransaction. Viene inoltre illustrato come usare i BeginTransactionmetodi , Commite Rollback .

private static void ExecuteSqlTransaction(string connectionString)
{
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        connection.Open();

        SqlCommand command = connection.CreateCommand();
        SqlTransaction transaction;

        // Start a local transaction.
        transaction = connection.BeginTransaction();

        // Must assign both transaction object and connection
        // to Command object for a pending local transaction
        command.Connection = connection;
        command.Transaction = transaction;

        try
        {
            command.CommandText =
                "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')";
            command.ExecuteNonQuery();
            command.CommandText =
                "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')";
            command.ExecuteNonQuery();

            // Attempt to commit the transaction.
            transaction.Commit();
            Console.WriteLine("Both records are written to database.");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Commit Exception Type: {0}", ex.GetType());
            Console.WriteLine("  Message: {0}", ex.Message);

            // Attempt to roll back the transaction.
            try
            {
                transaction.Rollback();
            }
            catch (Exception ex2)
            {
                // This catch block will handle any errors that may have occurred
                // on the server that would cause the rollback to fail, such as
                // a closed connection.
                Console.WriteLine("Rollback Exception Type: {0}", ex2.GetType());
                Console.WriteLine("  Message: {0}", ex2.Message);
            }
        }
    }
}

Private Sub ExecuteSqlTransaction(ByVal connectionString As String)
    Using connection As New SqlConnection(connectionString)
        connection.Open()

        Dim command As SqlCommand = connection.CreateCommand()
        Dim transaction As SqlTransaction

        ' Start a local transaction
        transaction = connection.BeginTransaction()

        ' Must assign both transaction object and connection
        ' to Command object for a pending local transaction.
        command.Connection = connection
        command.Transaction = transaction

        Try
            command.CommandText = _
              "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')"
            command.ExecuteNonQuery()
            command.CommandText = _
              "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')"

            command.ExecuteNonQuery()

            ' Attempt to commit the transaction.
            transaction.Commit()
            Console.WriteLine("Both records are written to database.")

        Catch ex As Exception
            Console.WriteLine("Commit Exception Type: {0}", ex.GetType())
            Console.WriteLine("  Message: {0}", ex.Message)

            ' Attempt to roll back the transaction.
            Try
                transaction.Rollback()

            Catch ex2 As Exception
                ' This catch block will handle any errors that may have occurred
                ' on the server that would cause the rollback to fail, such as
                ' a closed connection.
                Console.WriteLine("Rollback Exception Type: {0}", ex2.GetType())
                Console.WriteLine("  Message: {0}", ex2.Message)
            End Try
        End Try
    End Using
End Sub

Commenti

Il rollback della transazione può essere eseguito solo da uno stato in sospeso (dopo BeginTransaction essere stato chiamato, ma prima Commit di essere chiamato).

Note per gli implementatori

Quando si esegue l'override Rollback() in una classe derivata, assicurarsi di chiamare il metodo della classe di Rollback base.

Vedi anche

• Commit()
• BeginTransaction()