// ===============================================================
  public MySqlData executeMySqlSelect(String cmd) throws DevFailed {
    // long	t0 = System.currentTimeMillis();

    DeviceData argIn = new DeviceData();
    argIn.insert(cmd);
    DeviceData argout = ApiUtil.get_db_obj().command_inout("DbMySqlSelect", argIn);
    // long	t1 = System.currentTimeMillis();
    // System.out.println("elapsed time : " + (t1-t0) + " ms");

    return new MySqlData(argout.extractLongStringArray());
  }
  protected TangoUnitFactory() throws DevFailed {
    super();
    Database db = ApiUtil.get_db_obj();
    // try to find the singleton of TangoUnitFactory
    String[] devs = db.get_device_exported_for_class("TangoUnitFactory");

    if ((devs != null) && (devs.length > 0)) {
      // Get the first and unique TangounitFactory device
      proxy = new DeviceProxy(devs[0]);
    } else {
      throw new DevFailed(
          new DevError[] {
            new DevError(
                "No Tango Unit Factory defined or started in database",
                ErrSeverity.ERR,
                "The TangoUnit service need a factory that creates and start TangoUnit device",
                "TangoUnitFactory.init()")
          });
    }
  }