CREATE TABLE `students`
(
`id` INT AUTO_INCREMENT COMMENT '学生ID',
`name` VARCHAR(50) NOT NULL COMMENT '姓名',
`gender` ENUM ('男', '女') NOT NULL COMMENT '性别',
`birth_date` DATE COMMENT '出生日期',
`email` VARCHAR(100) COMMENT '邮箱',
`phone` VARCHAR(20) COMMENT '电话',
`address` VARCHAR(255) COMMENT '家庭地址',
`enrollment_date` DATE COMMENT '入学日期',
`status` ENUM ('在校', '毕业', '退学') DEFAULT '在校' COMMENT '状态',
PRIMARY KEY (`id`)
) COMMENT ='学生';
CREATE TABLE `courses`
(
`id` INT AUTO_INCREMENT COMMENT '课程ID',
`name` VARCHAR(100) NOT NULL COMMENT '课程名称',
`description` TEXT COMMENT '课程描述',
`credit` INT NOT NULL COMMENT '学分',
`teacher` VARCHAR(50) COMMENT '授课教师',
PRIMARY KEY (`id`)
) COMMENT ='课程';
CREATE TABLE `student_courses`
(
`id` INT AUTO_INCREMENT COMMENT '选课记录ID',
`student_id` INT NOT NULL COMMENT '学生ID',
`course_id` INT NOT NULL COMMENT '课程ID',
`enroll_date` DATE COMMENT '选课日期',
`grade` DECIMAL(5, 2) COMMENT '成绩',
PRIMARY KEY (`id`),
FOREIGN KEY (`student_id`) REFERENCES `students` (`id`) ON DELETE CASCADE,
FOREIGN KEY (`course_id`) REFERENCES `courses` (`id`) ON DELETE CASCADE
) COMMENT ='选课记录';