Как сравнить Bookmarks в таблице

function TBDEDirect.CompareBookmarks(Bookmark1, Bookmark2: TBookmark): Boolean;
var
  Res: DBIResult;
  CompareRes: Word;
begin
  Result := False;
  if CheckDatabase then
  begin
    Res := DbiCompareBookmarks(FDataLink.DataSource.DataSet.Handle,
    Bookmark1, Bookmark2, CompareRes);
    if Res = 0 then
      if CompareRes = 0 then
        Result := True
      else
    else
      Check(Res);
  end;
end;