Mariadb
OCaml-MariaDB is a library with OCaml bindings for MariaDB's libmysqlclient, including support for its nonblocking API. While you need MariaDB's libmysqlclient to build OCaml-MariaDB, it should be possible to use it with the regular libmysqlclient from MySQL, as long as you don't try to use the nonblocking API.