CREATE TABLE `user` (
  `id` int unsigned NOT NULL auto_increment,
  `username` VARCHAR(100) NOT NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `role` (
  `id` int unsigned NOT NULL auto_increment,
  `name` VARCHAR(25) NOT NULL UNIQUE,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `user_role` (
  `user` int unsigned NOT NULL,
  `role` int unsigned NOT NULL,
  PRIMARY KEY  (`user`,`role`),
  FOREIGN KEY (`user`) REFERENCES user(id),
  FOREIGN KEY (`role`) REFERENCES role(id)
) ENGINE=InnoDB;