text: # -- 删除原有数据库
  # DROP DATABASE `untitled`;
  #
  # -- 新建数据库
  # CREATE DATABASE `untitled`;
  
  -- 使用数据库
  USE `untitled`;
  
  # CREATE TABLE `user`
  # (
  #     `user_id`            int UNSIGNED NOT NULL AUTO_INCREMENT,
  #     `user_register_time` datetime     NOT NULL DEFAULT CURRENT_TIMESTAMP,
  #     `user_name`          varchar(20)  NOT NULL UNIQUE,
  #     `user_password_hash` varchar(32)  NOT NULL,
  #     `user_password_salt` varchar(32)  NOT NULL,
  #     `user_phone`         varchar(11) UNIQUE,
  #     PRIMARY KEY (`user_id`),
  #     INDEX (`user_name`)
  # ) ENGINE = InnoDB
  #   AUTO_INCREMENT = 100000
  #   DEFAULT CHARSET = utf8mb4;
  #
  # CREATE TABLE `admin`
  # (
  #     `user_id`            int UNSIGNED NOT NULL AUTO_INCREMENT,
  #     `user_register_time` datetime     NOT NULL DEFAULT CURRENT_TIMESTAMP,
  #     `user_name`          varchar(20)  NOT NULL UNIQUE,
  #     `user_password_hash` varchar(32)  NOT NULL,
  #     `user_password_salt` varchar(32)  NOT NULL,
  #     `user_phone`         varchar(11) UNIQUE,
  #     PRIMARY KEY (`user_id`),
  #     INDEX (`user_name`)
  # ) ENGINE = InnoDB
  #   AUTO_INCREMENT = 100000
  #   DEFAULT CHARSET = utf8mb4;
  
  DROP TABLE `employment`;
  DROP TABLE `user_skill`;
  DROP TABLE `skill`;
  DROP TABLE `duty`;
  
  CREATE TABLE `duty`
  (
      `duty_id`   int UNSIGNED NOT NULL AUTO_INCREMENT,
      `duty_name` varchar(20)  NOT NULL UNIQUE,
      `description` varchar(255),
      PRIMARY KEY (`duty_id`),
      INDEX (`duty_name`)
  ) ENGINE = InnoDB
    AUTO_INCREMENT = 0
    DEFAULT CHARSET = utf8mb4;
  
  
  CREATE TABLE `skill`
  (
      `skill_id`   int UNSIGNED NOT NULL AUTO_INCREMENT,
      `skill_name` varchar(20)  NOT NULL UNIQUE,
      PRIMARY KEY (`skill_id`),
      INDEX (`skill_name`)
  ) ENGINE = InnoDB
    AUTO_INCREMENT = 0
    DEFAULT CHARSET = utf8mb4;
  
  CREATE TABLE `employment`
  (
      `employment_id` int UNSIGNED NOT NULL,
      `duty_id`       int UNSIGNED NOT NULL,
      `skill_id`      int UNSIGNED NOT NULL,
      PRIMARY KEY (`employment_id`, `duty_id`, `skill_id`),
      FOREIGN KEY (`duty_id`) REFERENCES duty (`duty_id`),
      FOREIGN KEY (`skill_id`) REFERENCES skill (`skill_id`)
  ) ENGINE = InnoDB
    DEFAULT CHARSET = utf8mb4;
  
  CREATE TABLE `user_skill`
  (
      `user_id`  int UNSIGNED NOT NULL,
      `skill_id` int UNSIGNED NOT NULL,
      `proficiency` int UNSIGNED NOT NULL DEFAULT 3,
      PRIMARY KEY (`user_id`, `skill_id`),
      FOREIGN KEY (`user_id`) REFERENCES user (`user_id`),
      FOREIGN KEY (`skill_id`) REFERENCES skill (`skill_id`)
  ) ENGINE = InnoDB
    DEFAULT CHARSET = utf8mb4;