tab_xml_tmp = New System.Data.Odbc.OdbcDataAdapter("SELECT * FROM ***** WHERE" & _
  "L_LFDNR = '" & L_LFDNR & "';", con_Export_XML)
 
tab_xml_tmp.Fill(TmpDataSet)
DataReaderTmp = TmpDataSet.CreateDataReader()
 
          With DataReaderTmp
                Do While .Read
.....

sql_update_cmd = New Data.Odbc.OdbcCommand("UPDATE ***** SET DATE_TIME_STAMP =" & _
  "" & DatumZeitSQL(Now) & " WHERE L_LFDNR = " & L_LFDNR & ";", con_Export_XML)
                sql_update_cmd.ExecuteNonQuery()

Private con_Export_XML As New System.Data.Odbc.OdbcConnection( _
  "Dsn=XML_Export;uid=supervi")