You cannot set the OdbcCommand.Transaction property if it is already set to a specific value, and the command is in the process of executing. If you set the transaction property to an System.Data.Odbc.OdbcTransaction object that is not connected to the same System.Data.Odbc.OdbcConnection as the System.Data.Odbc.OdbcCommand object, an exception will be thrown the next time that you try to execute a statement.