[SOLVED] How to connect to mysql database with Erlang, Yaws

How to connect to mysql database with Erlang, Yaws

I am new to Erlang and Yaws... I am trying to connect to a mysql database but I am not sure about a few things..

Questions.
1. Do I need additional library to connect to mysql database with Erlang?
2. How Do I list available database drivers with Erlang?

I tried this code to connect.

application:start(odbc), 
ConnString = 
    "Driver={MySQL ODBC 5.1 Driver};" ++ 
    "Server=localhost;Database=db;" ++ 
    "User=root;Password=2eklmss;" ++ 
    "Option=3;", 
{ok, Conn} = odbc:connect(ConnString, []), 
Results = odbc:sql_query(Conn, "SELECT * FROM db"), 
{html,"Something here."}.

{I am not sure about this line

"Driver={MySQL ODBC 5.1 Driver};" ++

that is why I asked the 2th question }

and failed with following error:

ERROR erlang code threw an uncaught exception:
 File: /Users/username/Terminal/WebServerA/var/yaws/www/index.yaws:3
Class: error
Exception: undef
Req: {http_request,'GET',{abs_path,"/"},{1,1}}
Stack: [{odbc,connect,
              ["Driver={MySQL ODBC 5.1 Driver};Server=localhost;Database=db;User=root;Password= 2eklmss;Option=3;",
               []],
              []},
        {m22,out,1,
             [{file,"/Users/username/.yaws/yaws/default/m22.erl"},
              {line,19}]},
        {yaws_server,deliver_dyn_part,8,
                     [{file,"yaws_server.erl"},{line,2851}]},
        {yaws_server,aloop,4,[{file,"yaws_server.erl"},{line,1255}]},
        {yaws_server,acceptor0,2,[{file,"yaws_server.erl"},{line,1078}]},
        {proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]

I deleted all codes and only left this line.

out(A) -> 
    application:start(odbc).

The following error was occurred :

yaws code at /Users/username/Terminal/WebServerA/var/yaws/www/index.yaws:3 crashed or ret bad val:{error,
                                                                                                       {"no such file or directory",
                                                                                                        "odbc.app"}} 
Req: {http_request,'GET',{abs_path,"/"},{1,1}}

Solution

The error says that it can't find odbc application in its path. So it seems that there is a problem with your Erlang/OTP installation. As the Erlang ODBC application is dependent on third party products there are some notes here:

You need to make sure you have an ODBC driver installed.
You might need to set environment variables and paths to appropriate values.
If you built Erlang from source you may need to provide the path to your ODBC libraries using --with-odbc=PATH.

This manual could be helpful on how to compile ODBC on unix.

Also I suggest to take a look at Emysql as a stable third party alternative.