   `thread_id` bigint(20) NOT NULL DEFAULT '0',
   `depth` int(11) NOT NULL DEFAULT '0',
   `orderNum` int(11) NOT NULL DEFAULT '0',
-  `user_id` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL,
-  `title` varchar(200) COLLATE utf8mb4_unicode_ci NOT NULL,
-  `content` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
-  `in_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
-  `defunct` enum('N','Y') COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'N',
+  `user_id` varchar(20) NOT NULL,
+  `title` varchar(200) NOT NULL,
+  `content` longtext NOT NULL,
+  `in_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  `defunct` enum('N','Y') NOT NULL DEFAULT 'N',
   PRIMARY KEY (`message_id`),
   KEY `INDEX_user` (`user_id`) USING HASH,
   KEY `INDEX_problem` (`problem_id`) USING HASH,

  CONSTRAINT `FK_solution_contest` FOREIGN KEY (`contest_id`) REFERENCES `contest` (`contest_id`),
  CONSTRAINT `FK_solution_problem` FOREIGN KEY (`problem_id`) REFERENCES `problem` (`problem_id`),
  CONSTRAINT `FK_solution_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.solution_details
CREATE TABLE IF NOT EXISTS `solution_details` (
  `solution_id` bigint(20) NOT NULL,
  `details` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
  PRIMARY KEY (`solution_id`) USING HASH,
  CONSTRAINT `FK_solution_details_solution` FOREIGN KEY (`solution_id`) REFERENCES `solution` (`solution_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.source_code

  `source` blob NOT NULL,
  PRIMARY KEY (`solution_id`) USING HASH,
  CONSTRAINT `FK_source_code_solution` FOREIGN KEY (`solution_id`) REFERENCES `solution` (`solution_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.users
CREATE TABLE IF NOT EXISTS `users` (
  `user_id` varchar(20) NOT NULL,
  `email` varchar(255) NOT NULL DEFAULT '',
  `ip` varchar(39) DEFAULT NULL,
  `accesstime` datetime DEFAULT NULL,
  `volume` int(11) NOT NULL DEFAULT '1',
  `language` tinyint(4) NOT NULL DEFAULT '1',
  `password` varchar(100) NOT NULL,
  `reg_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `nick` varchar(255) NOT NULL DEFAULT '',
  `school` varchar(255) NOT NULL DEFAULT '',
  `style` tinyint(4) NOT NULL DEFAULT '41',
  `vcode` varchar(50) DEFAULT NULL,
  `defunct` enum('N','Y') NOT NULL DEFAULT 'N',
  `accepted` bigint(20) NOT NULL DEFAULT '0',
  `submit` bigint(20) NOT NULL DEFAULT '0',
  `solved` bigint(20) NOT NULL DEFAULT '0',
  `submit_problem` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`user_id`) USING HASH
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.user_problem
CREATE TABLE IF NOT EXISTS `user_problem` (
  `user_id` varchar(20) NOT NULL,
  `problem_id` bigint(20) NOT NULL,
  `accepted` bigint(20) NOT NULL DEFAULT '0',
  `submit` bigint(20) NOT NULL DEFAULT '0',
