sql表结构

后面的练习题，采用的表结构如下所示：

Course表：

对应的建表语句如下

CREATE TABLE `Course` (
  `c_id` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
  `c_name` varchar(20) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  `t_id` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
  `score` smallint(6) DEFAULT NULL,
  PRIMARY KEY (`c_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Score表：
**

对应的建表语句如下

CREATE TABLE `Score` (
  `s_id` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
  `c_id` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
  `s_score` int(3) DEFAULT NULL,
  PRIMARY KEY (`s_id`,`c_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Student表：



对应的建表语句如下

CREATE TABLE `Student` (
  `s_id` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
  `s_name` varchar(20) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  `s_birth` varchar(20) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  `s_sex` varchar(10) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  PRIMARY KEY (`s_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Teacher表：



对应的建表语句如下

CREATE TABLE `Teacher` (
  `t_id` varchar(20) COLLATE utf8_unicode_ci NOT NULL,
  `t_name` varchar(20) COLLATE utf8_unicode_ci NOT NULL DEFAULT '',
  PRIMARY KEY (`t_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci