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MySQL/OTP is a driver for connecting Erlang/OTP applications to MySQL and MariaDB databases. It is a native implementation of the MySQL protocol in Erlang.
Some of the features:
- Mnesia style transactions:
- Nested transactions are implemented using SQL savepoints.
- Transactions are automatically retried when deadlocks are detected.
- Each connection is a gen_server, which makes it compatible with Poolboy (for connection pooling) and ordinary OTP supervisors.
- SSL.
- Authentication methods
caching_sha2_password
(default from MySQL 8.0.4) andmysql_native_password
(default from MySQL 4.1). - Parametrized queries using cached unnamed prepared statements (What?)
- Slow queries are interrupted without killing the connection (MySQL version β₯ 5.0.0)
- Implements both protocols: the binary protocol for prepared statements and the text protocol for plain queries.
Requirements:
- Erlang/OTP version R16B or later
- MySQL database version 4.1 or later or MariaDB
- GNU Make or Rebar or any other tool for building Erlang/OTP applications
%% Connect (ssl is optional)
{ok, Pid} = mysql:start_link([{host, "localhost"}, {user, "foo"},
{password, "hello"}, {database, "test"},
{ssl, [{server_name_indication, disable},
{cacertfile, "/path/to/ca.pem"}]}]),
%% 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),
%% Close the connection
mysql:stop(Pid).
Using erlang.mk:
DEPS = mysql
dep_mysql = git https://github.com/mysql-otp/mysql-otp 1.8.0
Using rebar (version 2 or 3):
{deps, [
{mysql, ".*", {git, "https://github.com/mysql-otp/mysql-otp",
{tag, "1.8.0"}}}
]}.
Using mix:
{:mysql, git: "https://github.com/mysql-otp/mysql-otp", tag: "1.8.0"},
There's also a Hex package called mysql.
EUnit tests are executed using make tests
or make eunit
.
To run individual test suites, use make eunit t=SUITE
where SUITE is one of
mysql_encode_tests
, mysql_protocol_tests
, mysql_tests
, ssl_tests
or
transaction_tests
.
The encode and protocol test suites does not require a running MySQL server on localhost.
For the suites mysql_tests
, ssl_tests
and transaction_tests
you need to
start MySQL on localhost and give privileges to the users otptest
, otptest2
and (for ssl_tests
) to the user otptestssl
:
CREATE USER otptest@localhost IDENTIFIED BY 'OtpTest--123';
GRANT ALL PRIVILEGES ON otptest.* TO otptest@localhost;
CREATE USER otptest2@localhost IDENTIFIED BY 'OtpTest2--123';
GRANT ALL PRIVILEGES ON otptest.* TO otptest2@localhost;
-- in MySQL < 5.7, REQUIRE SSL must be given in GRANT
CREATE USER otptestssl@localhost IDENTIFIED BY 'OtpTestSSL--123';
GRANT ALL PRIVILEGES ON otptest.* TO otptestssl@localhost REQUIRE SSL;
-- in MySQL >= 8.0, REQUIRE SSL must be given in CREATE USER
CREATE USER otptestssl@localhost IDENTIFIED BY 'OtpTestSSL--123' REQUIRE SSL;
GRANT ALL PRIVILEGES ON otptest.* TO otptestssl@localhost;
Before running the test suite ssl_tests
you'll also need to generate SSL files
and MySQL extra config file. In order to do so, please execute make tests-prep
.
The MySQL server configuration must include my-ssl.cnf
file,
which can be found in test/ssl/
.
Do not run make tests-prep
after you start MySQL,
because CA certificates will no longer match.
If you run make tests COVER=1
a coverage report will be generated. Open
cover/index.html
to see that any lines you have added or modified are covered
by a test.
Run the tests and also dialyzer using make dialyze
.
Linebreak code to 80 characters per line and follow a coding style similar to that of existing code.
Keep commit messages short and descriptive. Each commit message should describe the purpose of the commit, the feature added or bug fixed, so that the commit log can be used as a comprehensive change log. CHANGELOG.md is generated from the commit messages.
This is for the project's maintainer(s) only.
Tagging a new version:
- Before tagging, update src/mysql.app.src and README.md with the new version.
- Tag and push tags using
git push --tags
. - After tagging a new version:
- Update the changelog using
make CHANGELOG.md
and commit it. - Update the online documentation and coverage reports using
make gh-pages
. Then push the gh-pages branch usinggit push origin gh-pages
.
Updating the Hex package (requires Mix):
make publish-hex
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 and COPYING.LESSER respectively.