OleDbTransaction.Rollback Metoda

Definice

Obor názvů:

System.Data.OleDb

Sestavení:

System.Data.OleDb.dll

Balíček:

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

Zdroj:

OleDbTransaction.cs

Vrátí transakci zpět z čekajícího stavu.

public:
 override void Rollback();

public override void Rollback ();

override this.Rollback : unit -> unit

Public Overrides Sub Rollback ()

Výjimky

Exception

Při pokusu o potvrzení transakce došlo k chybě.

InvalidOperationException

Transakce již byla potvrzena nebo vrácena zpět.

-nebo-

Připojení je přerušeno.

Příklady

Následující příklad vytvoří a OleDbConnectionOleDbTransaction. Ukazuje také, jak používat BeginTransactionmetody , Commita Rollback .

public void ExecuteTransaction(string connectionString)
{
    using (OleDbConnection connection =
               new OleDbConnection(connectionString))
    {
        OleDbCommand command = new OleDbCommand();
        OleDbTransaction transaction = null;

        // Set the Connection to the new OleDbConnection.
        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 OleDbConnection(connectionString)
        Dim command As New OleDbCommand()
        Dim transaction As OleDbTransaction

        ' Set the Connection to the new OleDbConnection.
        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

Poznámky

Transakce může být vrácena zpět pouze z čekajícího stavu (po BeginTransaction byla volána, ale před Commit je volána). Transakce bude vrácena zpět v případě, že je odstraněna před Commit nebo Rollback je volána.

Viz také

• Provádění transakcí