code: public BaseField getField(int iKeyFieldSeq)
      {
          if (this.getKeyField(iKeyFieldSeq) == null)
              return null;
          return this.getKeyField(iKeyFieldSeq).getField(DBConstants.FILE_KEY_AREA);
      }
docs: Get the Field in this KeyField.
  This is just a convenience to get the field from the KeyField.
  @param iKeyFieldSeq The position of this field in the key area.
  @return The field.