code: @Override
      public void unexportServer(final String serverName) throws DevFailed {
          final DeviceData argin = new DeviceData();
          argin.insert(serverName);
          database.command_inout("DbUnExportServer", argin);
      }
docs: Export a server into the tango db (execute DbUnExportServer on DB device)
  
  @param serverName
  The server name
  @throws DevFailed