text: CREATE TABLE blog
  (
    id int NOT NULL AUTO_INCREMENT COMMENT 'ID',
    blog_title varchar(255) NULL COMMENT '标题',
    blog_content text NULL COMMENT '内容',
    author_id int NOT NULL COMMENT '作者ID',
    create_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
    update_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
    PRIMARY KEY (id)
  ) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COMMENT '博客文章表';
  
  CREATE TABLE author
  (
    id int NOT NULL AUTO_INCREMENT COMMENT 'ID',
    user_name varchar(255) NULL COMMENT '作者名称',
    user_info text NULL COMMENT '简介',
    create_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
    update_time TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
    PRIMARY KEY (id)
  ) ENGINE=InnoDB  DEFAULT CHARSET=utf8  COMMENT '作者信息表';
  
  INSERT INTO author (user_name,user_info) values('zhang3','');
  INSERT INTO author (user_name,user_info) values('li4','');
  
  
  INSERT INTO blog (blog_title,blog_content,author_id) values('文章1','xxxxxx',1);
  INSERT INTO blog (blog_title,blog_content,author_id) values('文章2','xxxxxx',2);
  