Fix float data

README.md

@@ -113,7 +113,29 @@ If you are looking for the **plain necessities**, you should use the [ejabberd][
 
 #### Transaction
 
-This driver currently does not support transactions.
+This driver supports transaction in this way:
+
+Usage:
+
+```erlang
+Transaction = fun(Q) ->
+   R1 =  Q(<<"SELECT * from some_table">>, []),
+   R2 =  Q(<<"SELECT * from some_other_table">>, []),
+   R3 =  Q(<"INSERT INTO ...">>, []),
+   ....
+
+   {ok, SomeResult}
+end,
+
+{ok, Result} = emysql:transaction(Pool, Transaction,  Timeout).
+
+The transaction fun receive one argument, wich is also a function.
+That is used to perform queries.  Only textual queries allowed
+(no prepared statments with arguments).
+
+The result is the return value of the transaction function.
+If the function crashes, transaction is aborted. That is the only
+way to abort the transaction: throwing an error.
 
 For **mnesia-style transactions**, one of the multiple '[erlang-mysql-driver][22]s' may suite you best. There are [quite many][16] branches of it out there, and they are based on the same project as the ejabberd driver. To learn more about out the differences between the drivers, see the [mysql driver history][History].
 

src/emysql.erl

@@ -110,7 +110,7 @@
 %% Used to interact with the database.    
 -export([
             prepare/2,
-            execute/2, execute/3, execute/4, execute/5,
+            execute/2, execute/3, execute/4, execute/5, transaction/3,
             default_timeout/0
 ]).
 
@@ -533,6 +533,11 @@ execute(PoolId, Query, Timeout) when (is_list(Query) orelse is_binary(Query)) an
 execute(PoolId, StmtName, Timeout) when is_atom(StmtName), (is_integer(Timeout) orelse Timeout == infinity) ->
     execute(PoolId, StmtName, [], Timeout).
 
+transaction(PoolId, Fun, Timeout) when is_function(Fun) ->
+    Connection = emysql_conn_mgr:wait_for_connection(PoolId),
+    monitor_work(Connection, Timeout, {transaction, Connection, Fun}). 
+
+
 %% @spec execute(PoolId, Query|StmtName, Args, Timeout) -> Result | [Result]
 %%      PoolId = atom()
 %%      Query = binary() | string()
@@ -759,7 +764,14 @@ monitor_work(Connection0, Timeout, Args) when is_record(Connection0, emysql_conn
     {Pid, Mref} = spawn_monitor(
                     fun() ->
                             put(query_arguments, Args),
-                            Parent ! {self(), apply(fun emysql_conn:execute/3, Args)}
+                            %Parent ! {self(), apply(fun emysql_conn:execute/3, Args)}
+                            case Args of
+                                {transaction, _MaybeOtherConnection, Fun} ->
+                                    Result = execute_transaction(Connection, Fun),
+                                    Parent ! {self(), Result};
+                                _ ->
+                                    Parent ! {self(), apply(fun emysql_conn:execute/3, Args)}
+                            end
                     end),
     receive
         {'DOWN', Mref, process, Pid, tcp_connection_closed} ->
@@ -795,3 +807,43 @@ monitor_work(Connection0, Timeout, Args) when is_record(Connection0, emysql_conn
         emysql_conn:reset_connection(emysql_conn_mgr:pools(), Connection, pass),
         exit(mysql_timeout)
     end.
+
+%% @spec execute_transaction(Connection, Fun) -> Result
+%%      Connection = pid()
+%%      Fun = fun()
+
+%%      Result = ok_packet() | result_packet() | error_packet()
+%%
+%% @doc Execute a transaction function
+%%
+%% @private
+%% @end doc: jfjalburquerque july 15
+%%
+execute_transaction(Connection, Fun) ->
+    Result = try
+                 case emysql_conn:execute(Connection, <<"START TRANSACTION;">>, []) of
+                     #ok_packet{} ->
+                         %% execute transaction function
+                         Fun(fun(Query, Params) -> emysql_conn:execute(Connection, Query, Params) end);
+                     MysqlError -> MysqlError
+                 end
+             catch
+                 _:Error ->
+                     %% in case of error in the transaction function
+                     %% we send #error_packet to do rollback
+                     #error_packet{msg = Error}
+             end,
+    case Result of
+        #error_packet{} ->
+            %% in case of #error_packet we execute rollback
+            case emysql_conn:execute(Connection, <<"ROLLBACK;">>, []) of
+                #ok_packet{} -> Result#error_packet{code = 1402, status = <<"XA100">>};
+                RollbackError -> RollbackError
+            end;
+        _ ->
+            %% in case of #ok_packet we execute commit
+            case emysql_conn:execute(Connection, <<"COMMIT;">>, []) of
+                #ok_packet{} -> Result;
+                CommitError -> CommitError
+            end
+    end.

src/emysql_conn.erl

@@ -427,7 +427,7 @@ encode(Val, binary) when is_integer(Val) ->
     list_to_binary(integer_to_list(Val));
 encode(Val, list) when is_float(Val) ->
     [Res] = io_lib:format("~w", [Val]),
-    Res;
+    list_to_binary(Res);
 encode(Val, binary) when is_float(Val) ->
     iolist_to_binary(io_lib:format("~w", [Val]));
 encode({datetime, Val}, ReturnType) ->