ejabberd - Comments for "Mod_muc - mnesia:dirty_select need help"

And the revised

scothost — Thu, 29 Sep 2011 15:44:00 +0000

And the revised version

make_results({selected, ["name"], Items}) ->
[make_result(Item) || Item <- Items] .

make_result({Name}) ->
[{#muc_online_room{name_host = '$1', _ = '_'},
[{'==', {element, 1, '$1'}, Name }],
['$_']}].

Results = ejabberd_odbc:sql_query("suse1.local", ["SELECT name FROM location"]),
ListOfRooms = make_results(Results),
Pattern = lists:merge(ListOfRooms),
mnesia:dirty_select(muc_online_room,Pattern).

Hi Thanks for the reply I

scothost — Thu, 29 Sep 2011 15:30:21 +0000

Thanks for the reply

I figured it out. The problem was generating the list in the first place. I ended up with the code below that "appears" to work

make_results({selected, ["name"], Items}) ->
[make_result(Item) || Item <- Items] .

%% Execute the ODBC query and parse the result set
Results = ejabberd_odbc:sql_query("suse1.local", ["SELECT name FROM loc"]),
ListOfRooms = make_results(Results),

RoomString1 = [],

ListOfPatterns = lists:map(fun(X) ->
RoomString2 = [{#muc_online_room{name_host = '$1', _ = '_'},
[{'==', {element, 1, '$1'}, X }],
['$_']}],
string:concat(RoomString1,RoomString2)
end, ListOfRooms),
Pattern = lists:merge(ListOfPatterns),

mnesia:dirty_select(muc_online_room,Pattern).

You can specify a list of

skarab — Thu, 29 Sep 2011 13:11:38 +0000

You can specify a list of matches in your match spec to be passed to mnesia:dirty_select:

[{#muc_online_room{name_host = '$1', _ = '_'}, [{'==', {element, 1, '$1'}, Room}], ['$_']} || {Room} <- Rooms]

where Rooms is a list of rooms returned by your ODBC query. It is effectively the same as something like:

mnesia:dirty_select(muc_online_room,
  [{#muc_online_room{name_host = '$1', _ = '_'}, [{'==', {element, 1, '$1'}, "world"}], ['$_']},
   {#muc_online_room{name_host = '$1', _ = '_'}, [{'==', {element, 1, '$1'}, "world1"}], ['$_']},
   {#muc_online_room{name_host = '$1', _ = '_'}, [{'==', {element, 1, '$1'}, "test1"}], ['$_']}]).

I can't vouch for the performance of a very long list of matches though, so test it with a long list.