OdbcTransaction.Rollback Metodo

Definizione

Spazio dei nomi:

System.Data.Odbc

Assembly:

System.Data.Odbc.dll

Pacchetto:

System.Data.Odbc v9.0.0-rc.2.24473.5

Origine:

OdbcTransaction.cs

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

public:
 override void Rollback();

public override void Rollback ();

override this.Rollback : unit -> unit

Public Overrides 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 viene creato un OdbcConnection oggetto e un OdbcTransactionoggetto . Illustra anche come usare i BeginTransactionmetodi , Commite Rollback .

public static void ExecuteTransaction(string connectionString)
{
    using (OdbcConnection connection =
               new OdbcConnection(connectionString))
    {
        OdbcCommand command = new OdbcCommand();
        OdbcTransaction transaction = null;

        // Set the Connection to the new OdbcConnection.
        command.Connection = connection;

        // Open the connection and execute the transaction.
        try
        {
            connection.Open();

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

            // Assign transaction object for a pending local transaction.
            command.Connection = connection;
            command.Transaction = transaction;

            // Execute the commands.
            command.CommandText =
                "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')";
            command.ExecuteNonQuery();
            command.CommandText =
                "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')";
            command.ExecuteNonQuery();

            // Commit the transaction.
            transaction.Commit();
            Console.WriteLine("Both records are written to database.");
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
            try
            {
                // Attempt to roll back the transaction.
                transaction.Rollback();
            }
            catch
            {
                // Do nothing here; transaction is not active.
            }
        }
        // The connection is automatically closed when the
        // code exits the using block.
    }
}

Public Sub ExecuteTransaction(ByVal connectionString As String)

    Using connection As New OdbcConnection(connectionString)
        Dim command As New OdbcCommand()
        Dim transaction As OdbcTransaction

        ' Set the Connection to the new OdbcConnection.
        command.Connection = connection

        ' Open the connection and execute the transaction.
        Try
            connection.Open()

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

            ' Assign transaction object for a pending local transaction.
            command.Connection = connection
            command.Transaction = transaction

            ' Execute the commands.
            command.CommandText =
                "Insert into Region (RegionID, RegionDescription) VALUES (100, 'Description')"
            command.ExecuteNonQuery()
            command.CommandText =
                "Insert into Region (RegionID, RegionDescription) VALUES (101, 'Description')"
            command.ExecuteNonQuery()

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

        Catch ex As Exception
            Console.WriteLine(ex.Message)
            ' Try to rollback the transaction
            Try
                transaction.Rollback()

            Catch
                ' Do nothing here; transaction is not active.
            End Try
        End Try
        ' The connection is automatically closed when the
        ' code exits the Using block.
    End Using
End Sub

Commenti

La transazione può essere eseguito il rollback solo da uno stato in sospeso (dopo BeginTransaction essere stato chiamato, ma prima Commit viene chiamato). La transazione verrà eseguito il rollback nell'evento eliminato prima Commit o Rollback viene chiamato.

Vedi anche

• Esecuzione di transazioni