   PRIMARY KEY (`problem_id`),
   KEY `FK_problem_contest` (`contest_id`),
   CONSTRAINT `FK_problem_contest` FOREIGN KEY (`contest_id`) REFERENCES `contest` (`contest_id`)
-) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- Data exporting was unselected.
 -- Dumping structure for table clanguage.problem_i18n
 CREATE TABLE IF NOT EXISTS `problem_i18n` (
   `id` bigint(20) NOT NULL,
-  `locale` enum('en','zh') COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'zh',
-  `title` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
-  `description` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
-  `input` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
-  `output` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
-  `hint` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
-  `source` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
+  `locale` enum('en','zh') NOT NULL DEFAULT 'zh',
+  `title` longtext NOT NULL,
+  `description` longtext NOT NULL,
+  `input` longtext NOT NULL,
+  `output` longtext NOT NULL,
+  `hint` longtext NOT NULL,
+  `source` longtext NOT NULL,
   PRIMARY KEY (`id`,`locale`) USING HASH,
   CONSTRAINT `FK_problem` FOREIGN KEY (`id`) REFERENCES `problem` (`problem_id`)
-) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- Data exporting was unselected.
 -- Dumping structure for table clanguage.solution
 CREATE TABLE IF NOT EXISTS `solution` (
   `solution_id` bigint(20) NOT NULL,
   `problem_id` bigint(20) NOT NULL,
-  `user_id` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL,
+  `user_id` varchar(20) NOT NULL,
   `time` bigint(20) NOT NULL DEFAULT '0',
   `memory` bigint(20) NOT NULL DEFAULT '0',
   `in_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
   `score` smallint(6) NOT NULL DEFAULT '0',
   `language` tinyint(4) NOT NULL,
-  `ip` varchar(39) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
+  `ip` varchar(39) NOT NULL DEFAULT '',
   `contest_id` bigint(20) DEFAULT NULL,
   `num` tinyint(4) NOT NULL DEFAULT '-1',
   `code_length` int(11) NOT NULL DEFAULT '0',

  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

  CONSTRAINT `FK_message_message` FOREIGN KEY (`parent_id`) REFERENCES `message` (`message_id`),
  CONSTRAINT `FK_message_problem` FOREIGN KEY (`problem_id`) REFERENCES `problem` (`problem_id`),
  CONSTRAINT `FK_message_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='讨论版';

-- Data exporting was unselected.
-- Dumping structure for table clanguage.news
CREATE TABLE IF NOT EXISTS `news` (
  `news_id` bigint(20) NOT NULL,
  `user_id` varchar(20) NOT NULL,
  `title` varchar(200) NOT NULL DEFAULT '',
  `content` longtext NOT NULL,
  `time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `importance` tinyint(4) NOT NULL DEFAULT '0',
  `defunct` enum('N','Y') NOT NULL DEFAULT 'N',
  PRIMARY KEY (`news_id`),
  KEY `INDEX_users` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.persistent_logins
CREATE TABLE IF NOT EXISTS `persistent_logins` (
  `username` varchar(64) NOT NULL,
  `series` varchar(64) NOT NULL,
  `token` varchar(64) NOT NULL,
  `last_used` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`series`) USING HASH,
  KEY `Index_username` (`username`) USING HASH
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.privilege
CREATE TABLE IF NOT EXISTS `privilege` (
  `user_id` varchar(20) NOT NULL,
  `rightstr` enum('administrator','source_browser','news_publisher') NOT NULL DEFAULT 'news_publisher' COMMENT 'news_publisher没有用到',
  `defunct` enum('N','Y') NOT NULL DEFAULT 'N' COMMENT 'Y表示暂时禁用，N表示可用',
  PRIMARY KEY (`user_id`) USING HASH,
  CONSTRAINT `FK_privilege_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- Data exporting was unselected.
-- Dumping structure for table clanguage.problem
CREATE TABLE IF NOT EXISTS `problem` (
  `problem_id` bigint(20) NOT NULL,
  `title` varchar(255) NOT NULL,
  `description` longtext NOT NULL,
  `input` longtext NOT NULL,
  `output` longtext NOT NULL,
  `sample_input` longtext NOT NULL,
  `sample_output` longtext NOT NULL,
  `hint` longtext NOT NULL,
  `source` varchar(255) NOT NULL,
  `in_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `time_limit` int(11) NOT NULL,
  `memory_limit` int(11) NOT NULL,
  `defunct` enum('N','Y') NOT NULL DEFAULT 'N',
  `contest_id` bigint(20) DEFAULT NULL,
  `accepted` bigint(20) NOT NULL DEFAULT '0',
  `submit` bigint(20) NOT NULL DEFAULT '0',
