text: create database MemoDao;
  
  use MemoDao;
  drop table tb_memo;
  create table tb_memo(
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `username` varchar(20) NOT NULL,
    `title` varchar(20) NOT NULL,
    `content` varchar(200) NOT NULL,
    `memotype` varchar(20) NOT NULL,
    `memotime` varchar(10) NOT NULL,
    PRIMARY KEY (`id`)
  );
  
  INSERT INTO `tb_memo` (`id`,`username`,`title`,`content`,`memotype`,`memotime`) 
  VALUES (1,"小明","文稿","今天要开会","会议","2016-03-05");
  
  select * from tb_memo;