docs: public KeyArea setKeyArea(BaseField fldFirstFieldInKey)
      {
          for (int i = 0; i < this.getKeyAreaCount(); i++)
          {
              KeyArea keyArea = this.getKeyArea(i);
              BaseField fieldFirst = keyArea.getKeyField(DBConstants.MAIN_KEY_FIELD).getField(DBConstants.FILE_KEY_AREA);
              if (fieldFirst == fldFirstFieldInKey)
              {
                  return this.setKeyArea(i);
              }
          }
          return null;    // Not found
      }