Erlang/OTP Forums

-record(user, {uid, login, password}).
-record(line, {lid, phone, state}).
-record(call, {cid, uid, lid, date, time, log}).
  mnesia:create_table(user, [{disc_copies, [node()]}, {attributes, record_info(fields, user)}, {index, [login]}]),
  mnesia:create_table(line, [{disc_copies, [node()]}, {attributes, record_info(fields, line)}, {index, [phone]}]),
  mnesia:create_table(call, [{disc_copies, [node()]}, {attributes, record_info(fields, call)}, {index, [date,uid,lid]}]).

% find N top callers for period F-T
plain_usertop(N,{FD,FT},{TD,TT}) ->
    FM=FD+FT, TM=TD+TT,
    Logs = loadLogs(call, #call.date, FD, TD),
    CalcStat = fun
      (#call{uid=Id, date=D, time=T, log={success, Dur}}, Stat)
        when (D+T=<TM) andalso (D+T>=FM) ->
          orddict:update(Id, fun(O)->O+Dur end, Dur, Stat);
      (_, Stat) -> Stat
    end,
    Stat = lists:foldl(CalcStat, orddict:new(), Logs),
    StatL = orddict:to_list(Stat),
    StatSort = lists:keysort(2, StatL),
    if N > length(StatSort) -> lists:reverse(StatSort);
       ?ELSE -> lists:reverse(lists:nthtail(length(StatSort)-N,StatSort))
    end.

loadLogs(Table, Key, FstDate, LstDate) ->
    loadLogs(Table, Key, FstDate, LstDate, undefined, []).
loadLogs(Table, Key, FstDate, LstDate, SortField) ->
    loadLogs(Table, Key, FstDate, LstDate, SortField, []).
loadLogs(Table, Key, FstDate, LstDate, SortField, CurLogs) ->
    Logs = mnesia:dirty_index_read(Table, FstDate, Key),
    if (SortField=/=undefined) -> SLogs = lists:keysort(SortField, Logs); ?ELSE -> SLogs = Logs end,
    NewLogs = CurLogs++SLogs,
    if FstDate < LstDate ->
      loadLogs(Table, Key, FstDate+1000000*?SECONDS_PER_DAY, LstDate, SortField, NewLogs);
    ?ELSE ->
      NewLogs
    end.

loadLogs(...) ->
Handle = qlc:q([X || X <- mnesia:table(call),
          X#call.date>=FstData,
          X#call.date=<LstData]),
    {atomic, Cursor} =
           mnesia:transaction(fun() ->qlc:cursor(Handle) end),
Cursor.

qlc:next_answers(Cursor[, Num]). %%default 10