MySQL/OTP
=========
[](https://travis-ci.org/mysql-otp/mysql-otp)
MySQL/OTP is a driver for connecting Erlang/OTP applications to MySQL
databases. It is a native implementation of the MySQL protocol in Erlang.
Some of the features:
* Mnesia style transactions:
* Nested transactions are implemented using savepoints.
* Transactions are automatically retried when deadlocks are detected.
* Uses the binary protocol for prepared statements.
* Each connection is a gen_server, which makes it compatible with Poolboy (for
connection pooling) and ordinary OTP supervisors.
* No records in the public API.
* Slow queries are interrupted without killing the connection (MySQL version
≥ 5.0.0).
See also:
* [API documenation](//mysql-otp.github.io/mysql-otp/index.html) (Edoc)
* [Test coverage](//mysql-otp.github.io/mysql-otp/eunit.html) (EUnit)
* [Why another MySQL driver?](https://github.com/mysql-otp/mysql-otp/wiki#why-another-mysql-driver) in the wiki
* [MySQL/OTP + Poolboy](https://github.com/mysql-otp/mysql-otp-poolboy):
A simple application that combines MySQL/OTP with Poolboy for connection
pooling.
Synopsis
--------
```Erlang
%% Connect
{ok, Pid} = mysql:start_link([{host, "localhost"}, {user, "foo"},
{password, "hello"}, {database, "test"}]),
%% Select
{ok, ColumnNames, Rows} =
mysql:query(Pid, <<"SELECT * FROM mytable WHERE id = ?">>, [1]),
%% Manipulate data
ok = mysql:query(Pid, "INSERT INTO mytable (id, bar) VALUES (?, ?)", [1, 42]),
%% Separate calls to fetch more info about the last query
LastInsertId = mysql:insert_id(Pid),
AffectedRows = mysql:affected_rows(Pid),
WarningCount = mysql:warning_count(Pid),
%% Mnesia style transaction (nestable)
Result = mysql:transaction(Pid, fun () ->
ok = mysql:query(Pid, "INSERT INTO mytable (foo) VALUES (1)"),
throw(foo),
ok = mysql:query(Pid, "INSERT INTO mytable (foo) VALUES (1)")
end),
case Result of
{atomic, ResultOfFun} ->
io:format("Inserted 2 rows.~n");
{aborted, Reason} ->
io:format("Inserted 0 rows.~n")
end
%% Multiple queries and multiple result sets
{ok, [{[<<"foo">>], [[42]]}, {[<<"bar">>], [[<<"baz">>]]}]} =
mysql:query(Pid, "SELECT 42 AS foo; SELECT 'baz' AS bar;"),
%% Graceful timeout handling: SLEEP() returns 1 when interrupted
{ok, [<<"SLEEP(5)">>], [[1]]} =
mysql:query(Pid, <<"SELECT SLEEP(5)">>, 1000),
```
Usage as a dependency
---------------------
Using *erlang.mk*:
DEPS = mysql
dep_mysql = git https://github.com/mysql-otp/mysql-otp 1.0.0
Using *rebar*:
{deps, [
{mysql, ".*", {git, "https://github.com/mysql-otp/mysql-otp",
{tag, "1.0.0"}}}
]}.
Tests
-----
Run the eunit tests with `make eunit`. The tests need an executable `rebar` in
the `$PATH`. For the suite `mysql_tests` you need MySQL running on localhost
and give privileges to the `otptest` user:
```SQL
grant all privileges on otptest.* to otptest@localhost identified by 'otptest';
```
License
-------
GNU Lesser General Public License (LGPL) version 3 or any later version.
Since the LGPL is a set of additional permissions on top of the GPL, both
license texts are included in the files [COPYING](COPYING) and
[COPYING.LESSER](COPYING.LESSER) respectively.
We hope this license should be permissive enough while remaining copyleft. If
you're having issues with this license, please create an issue in the issue
tracker!
