SQL 数据库设计：学生表和课程表创建与多对多关系实现

创建学生表student的SQL语句如下：\n\nCREATE TABLE student (\n Stuid int PRIMARY KEY AUTO_INCREMENT,\n StuName varchar(50) NOT NULL,\n StuGender varchar(2) DEFAULT '男',\n StuAge int(2) CHECK (StuAge >= 0),\n StuEmail varchar(50) UNIQUE\n);\n\n添加五条测试语句：\n\nINSERT INTO student (StuName, StuGender, StuAge, StuEmail) VALUES ('张三', '男', 20, 'zhangsan@example.com');\nINSERT INTO student (StuName, StuGender, StuAge, StuEmail) VALUES ('李四', '男', 21, 'lisi@example.com');\nINSERT INTO student (StuName, StuGender, StuAge, StuEmail) VALUES ('王五', '男', 22, 'wangwu@example.com');\nINSERT INTO student (StuName, StuGender, StuAge, StuEmail) VALUES ('赵六', '男', 23, 'zhaoliu@example.com');\nINSERT INTO student (StuName, StuGender, StuAge, StuEmail) VALUES ('小红', '女', 19, 'xiaohong@example.com');\n\n创建课程表course的SQL语句如下：\n\nCREATE TABLE course (\n CourseId int PRIMARY KEY AUTO_INCREMENT,\n CourseName varchar(50) NOT NULL\n);\n\n添加三条测试语句：\n\nINSERT INTO course (CourseName) VALUES ('数学');\nINSERT INTO course (CourseName) VALUES ('英语');\nINSERT INTO course (CourseName) VALUES ('物理');\n\n创建学生和课程的中间表middle_table的SQL语句如下：\n\nCREATE TABLE middle_table (\n Stuid int,\n CourseId int,\n PRIMARY KEY (Stuid, CourseId),\n FOREIGN KEY (Stuid) REFERENCES student(Stuid) ON DELETE CASCADE,\n FOREIGN KEY (CourseId) REFERENCES course(CourseId) ON DELETE CASCADE\n);\n\n添加注释：\n\nCOMMENT ON TABLE student IS '学生表';\nCOMMENT ON COLUMN student.Stuid IS '学生编号';\nCOMMENT ON COLUMN student.StuName IS '学生名称';\nCOMMENT ON COLUMN student.StuGender IS '学生性别';\nCOMMENT ON COLUMN student.StuAge IS '学生年龄';\nCOMMENT ON COLUMN student.StuEmail IS '学生邮箱';\n\nCOMMENT ON TABLE course IS '课程表';\nCOMMENT ON COLUMN course.CourseId IS '课程编号';\nCOMMENT ON COLUMN course.CourseName IS '课程名称';\n\nCOMMENT ON TABLE middle_table IS '学生课程关系表';