d_prepared_statement.erl

% ------------------------------------------------------------------------
% Emysql: Prepared Statement, a minimal sample
% H. Diedrich <hd2010@eonblast.com> - Eonblast http://www.eonblast.com
% 12 Jun 2010
% ------------------------------------------------------------------------
%
% Create local mysql database (or re-use the one made for a_hello):
%
% $ mysql ...
% mysql> create database hello_database;
% mysql> use hello_database;
% mysql> create table hello_table (hello_text char(20));
% mysql> grant all privileges on hello_database.* to hello_username@localhost identified by 'hello_password';
% mysql> quit
%
% On *nix build and run using the batch a_hello in folder samples/:
%
% $ ./d_prepared_statement
%
% - or - 
%
% Make emysql and start this sample directly, along these lines:
%
% $ cd Emysql
% $ make
% $ cd samples
% $ erlc d_prepared_statement.erl
% $ erl -pa ../ebin -s d_prepared_statement run -s init stop -noshell
%
% ------------------------------------------------------------------------
%
% Expected Output:
%
% ...
% ... many PROGRESS REPORT lines ...
% ...
%
% Result: {result_packet,32,
%                      [{field,2,<<"def">>,<<"hello_database">>,
%                               <<"hello_table">>,<<"hello_table">>,
%                               <<"hello_text">>,<<"hello_text">>,254,<<>>,33,
%                               60,0,0}],
%                       [[<<"Hello World!">>]],
%                       <<>>}
%
% ------------------------------------------------------------------------

-module(d_prepared_statement).
-export([run/0]).

run() ->

	application:start(sasl),
	crypto:start(),
	application:start(emysql),

	emysql:add_pool(hello_pool, [{size,1},
				     {user,"hello_username"},
				     {password,"hello_password"},
				     {database,"hello_database"},
				     {encoding,utf8}]),

	emysql:execute(hello_pool,
		<<"INSERT INTO hello_table SET hello_text = 'Hello World!'">>),

	%% ------------------------------------------------------------------- 
	%% Stored procedure:
	%% - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

	emysql:prepare(hello_stmt, 
		<<"SELECT * from hello_table WHERE hello_text like ?">>),

	Result = emysql:execute(hello_pool, hello_stmt, ["Hello%"]),

	%% ------------------------------------------------------------------- 

	io:format("~n~s~n", [string:chars($-,72)]),
	io:format("Result: ~p~n", [Result]),

    ok.