docs: public FieldInfo getCounterField()
      {
          KeyArea keyArea = this.getKeyArea(DBConstants.MAIN_KEY_AREA);
          if (keyArea != null)
          {
              BaseField fldID = keyArea.getKeyField(DBConstants.MAIN_KEY_FIELD).getField(DBConstants.FILE_KEY_AREA);
              if (fldID instanceof CounterField)
                  return (CounterField)fldID;
          }
          return null;    // None
      }