MySql-学生成绩管理系统

前言

暑假的时候学习过这个 MySql 数据库，然后学校这个学期居然开了这门课程，那就做一个学生成绩管理系统来练一练手吧。在这里做一个简单的练习记录。

需求分析

SQL 编写

新建数据库

为该数据库建表

INSERT INTO 数据

创建索引

创建视图

创建触发器

创建存储过程

SQL 查询进行调试

结语

完整代码如下

-- 1. 新建数据库 drop database studentManage; CREATE DATABASE studentManage; use studentManage;  -- 2. 创建表  -- 创建班级表 CREATE TABLE classes ( class_id INT PRIMARY KEY,  -- 班级ID，作为主键 class_name VARCHAR(50)  -- 班级名称，最大长度为50个字符 );  -- 插入班级数据 INSERT INTO classes (class_id, class_name) VALUES (0, '尖子班'); INSERT INTO classes (class_id, class_name) VALUES (1, '垃圾班'); INSERT INTO classes (class_id, class_name) VALUES (2, '垃圾班'); INSERT INTO classes (class_id, class_name) VALUES (3, '废物班'); INSERT INTO classes (class_id, class_name) VALUES (4, '废物班'); INSERT INTO classes (class_id, class_name) VALUES (5, '脑残班');  -- 创建学生表 CREATE TABLE students ( student_id INT PRIMARY KEY NOT NULL,  -- 学生ID，作为主键，不允许为空 name VARCHAR(50),  -- 姓名，最大长度为50个字符 class_id INT,  -- 班级ID age INT,  -- 年龄 FOREIGN KEY (class_id) REFERENCES classes(class_id)  -- 外键关联到班级表的班级ID );  -- 插入学生数据 INSERT INTO students (student_id, name, class_id, age) VALUES (1, '王八', 5, 19); INSERT INTO students (student_id, name, class_id, age) VALUES (2, '王一', 1, 20); INSERT INTO students (student_id, name, class_id, age) VALUES (3, '小六', 0, 18); INSERT INTO students (student_id, name, class_id, age) VALUES (4, '王五', 2, 19); INSERT INTO students (student_id, name, class_id, age) VALUES (5, '赵六', 3, 20); INSERT INTO students (student_id, name, class_id, age) VALUES (6, '小七', 4, 18);  -- 创建教师表 CREATE TABLE teachers ( teacher_id INT PRIMARY KEY NOT NULL,  -- 教师ID，作为主键，不允许为空 teacher_name VARCHAR(50)  -- 教师姓名，最大长度为50个字符 );  -- 插入教师数据 INSERT INTO teachers (teacher_id, teacher_name) VALUES (1, '陈老师'); INSERT INTO teachers (teacher_id, teacher_name) VALUES (2, '杨老师'); INSERT INTO teachers (teacher_id, teacher_name) VALUES (4, '何老师'); INSERT INTO teachers (teacher_id, teacher_name) VALUES (4, '刘老师'); INSERT INTO teachers (teacher_id, teacher_name) VALUES (5, '陈老师'); INSERT INTO teachers (teacher_id, teacher_name) VALUES (6, '周老师');  -- 创建课程表 CREATE TABLE courses ( course_id INT PRIMARY KEY NOT NULL,  -- 课程ID，作为主键，不允许为空 course_name VARCHAR(50),  -- 课程名称，最大长度为50个字符 teacher_id INT,  -- 教师ID FOREIGN KEY (teacher_id) REFERENCES teachers(teacher_id)  -- 外键关联到教师表的教师ID );  -- 插入课程数据 INSERT INTO courses (course_id, course_name, teacher_id) VALUES (100, '英语', 1); INSERT INTO courses (course_id, course_name, teacher_id) VALUES (101, '语文', 2); INSERT INTO courses (course_id, course_name, teacher_id) VALUES (102, '数学', 3); INSERT INTO courses (course_id, course_name, teacher_id) VALUES (103, '生物', 4); INSERT INTO courses (course_id, course_name, teacher_id) VALUES (104, '物理', 5); INSERT INTO courses (course_id, course_name, teacher_id) VALUES (105, '化学', 6);  -- 创建成绩表 CREATE TABLE scores ( student_id INT,  -- 学生ID course_id INT,  -- 课程ID score INT,  -- 分数 FOREIGN KEY (student_id) REFERENCES students(student_id),  -- 外键关联到学生表的学生ID FOREIGN KEY (course_id) REFERENCES courses(course_id)  -- 外键关联到课程表的课程ID );  -- 插入成绩数据 INSERT INTO scores (student_id, course_id, score) VALUES (1, 1, 92); INSERT INTO scores (student_id, course_id, score) VALUES (2, 1, 8); INSERT INTO scores (student_id, course_id, score) VALUES (3, 1, 5); INSERT INTO scores (student_id, course_id, score) VALUES (4, 1, 0); INSERT INTO scores (student_id, course_id, score) VALUES (5, 1, 8); INSERT INTO scores (student_id, course_id, score) VALUES (6, 1, 7);  INSERT INTO scores (student_id, course_id, score) VALUES (1, 2, 100); INSERT INTO scores (student_id, course_id, score) VALUES (2, 2, 8); INSERT INTO scores (student_id, course_id, score) VALUES (3, 2, 5); INSERT INTO scores (student_id, course_id, score) VALUES (4, 2, 2); INSERT INTO scores (student_id, course_id, score) VALUES (5, 2, 8); INSERT INTO scores (student_id, course_id, score) VALUES (6, 2, 7);  INSERT INTO scores (student_id, course_id, score) VALUES (1, 1, 100); INSERT INTO scores (student_id, course_id, score) VALUES (2, 2, 1); INSERT INTO scores (student_id, course_id, score) VALUES (3, 3, 7); INSERT INTO scores (student_id, course_id, score) VALUES (4, 4, 10); INSERT INTO scores (student_id, course_id, score) VALUES (5, 5, 10); INSERT INTO scores (student_id, course_id, score) VALUES (6, 6, 60);  INSERT INTO scores (student_id, course_id, score) VALUES (1, 1, 100); INSERT INTO scores (student_id, course_id, score) VALUES (2, 2, 22); INSERT INTO scores (student_id, course_id, score) VALUES (3, 3, 71); INSERT INTO scores (student_id, course_id, score) VALUES (4, 4, 20); INSERT INTO scores (student_id, course_id, score) VALUES (5, 5, 30); INSERT INTO scores (student_id, course_id, score) VALUES (6, 6, 40);  INSERT INTO scores (student_id, course_id, score) VALUES (1, 1, 100); INSERT INTO scores (student_id, course_id, score) VALUES (2, 2, 14); INSERT INTO scores (student_id, course_id, score) VALUES (3, 3, 72); INSERT INTO scores (student_id, course_id, score) VALUES (4, 4, 11); INSERT INTO scores (student_id, course_id, score) VALUES (5, 5, 11); INSERT INTO scores (student_id, course_id, score) VALUES (6, 6, 62);  INSERT INTO scores (student_id, course_id, score) VALUES (1, 1, 100); INSERT INTO scores (student_id, course_id, score) VALUES (2, 2, 12); INSERT INTO scores (student_id, course_id, score) VALUES (3, 3, 73); INSERT INTO scores (student_id, course_id, score) VALUES (4, 4, 14); INSERT INTO scores (student_id, course_id, score) VALUES (5, 5, 15); INSERT INTO scores (student_id, course_id, score) VALUES (6, 6, 66);  -- 3. 创建索引 -- 为学生表的学生ID创建索引 CREATE INDEX idx_student_id ON students (student_id);  -- 为课程表的课程ID创建索引 CREATE INDEX idx_course_id ON courses (course_id);  -- 为成绩表的学生ID和课程ID创建联合索引 CREATE INDEX idx_student_course ON scores (student_id, course_id);  -- 4. 创建视图 CREATE VIEW class_scores AS     SELECT          c.class_id,          c.class_name,          COUNT(s.student_id) AS student_count,          AVG(sc.score) AS average_score     FROM          classes c     JOIN          students s ON c.class_id = s.class_id     JOIN     scores sc ON s.student_id = sc.student_id GROUP BY          c.class_id, c.class_name;  CREATE VIEW teacher_courses AS   SELECT        t.teacher_id,        t.teacher_name,        COUNT(c.course_id) AS course_count   FROM        teachers t   JOIN        courses c ON t.teacher_id = c.teacher_id   GROUP BY        t.teacher_id, t.teacher_name;   -- 5. 创建触发器  DELIMITER //   CREATE TRIGGER check_student_class_id_after_insert   AFTER INSERT ON students   FOR EACH ROW   BEGIN       IF NEW.class_id IS NULL OR NEW.class_id = 0 THEN           SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = '必须为新学生分配班级ID';       END IF;   END;   //   DELIMITER ;  DELIMITER //   CREATE TRIGGER check_course_name_length_before_update   BEFORE UPDATE ON courses   FOR EACH ROW   BEGIN       IF NEW.course_name IS NOT NULL AND LENGTH(NEW.course_name) > 50 THEN           SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = '课程名称长度不能超过50个字符';       END IF;   END;   //   DELIMITER ;  DELIMITER //   CREATE TRIGGER check_student_scores_after_delete   AFTER DELETE ON students   FOR EACH ROW   BEGIN       DECLARE score_count INT;       SELECT COUNT(*) INTO score_count FROM scores WHERE student_id = OLD.student_id;       IF score_count > 0 THEN           SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = '不能删除有分数记录的学生';       END IF;   END;   //   DELIMITER ;  -- 6. 创建存储函数 -- 存储过程1 - 添加学生 DELIMITER //  CREATE PROCEDURE add_student (     IN p_student_id INT,     IN p_name VARCHAR(50),     IN p_class_id INT,     IN p_age INT ) BEGIN     INSERT INTO students (student_id, name, class_id, age) VALUES (p_student_id, p_name, p_class_id, p_age); END //  DELIMITER ;  -- 存储过程2 - 添加课程 DELIMITER //  CREATE PROCEDURE add_course (     IN p_course_id INT,     IN p_course_name VARCHAR(50),     IN p_teacher_id INT ) BEGIN     INSERT INTO courses (course_id, course_name, teacher_id) VALUES (p_course_id, p_course_name, p_teacher_id); END //  DELIMITER ;  -- 存储过程3 - 添加成绩 DELIMITER //  CREATE PROCEDURE add_score (     IN p_student_id INT,     IN p_course_id INT,     IN p_score INT ) BEGIN     INSERT INTO scores (student_id, course_id, score) VALUES (p_student_id, p_course_id, p_score); END //  DELIMITER ;  -- 数据更新 -- 更新学生的姓名 UPDATE students SET name = '新名字' WHERE student_id = 1;  -- 更新学生的班级 UPDATE students SET class_id = 1 WHERE student_id = 2;  -- 更新学生的年龄 UPDATE students SET age = 21 WHERE student_id = 3;  -- 更新课程的名称 UPDATE courses SET course_name = '历史' WHERE course_id = 100;  -- 更新课程的教师 UPDATE courses SET teacher_id = 2 WHERE course_id = 101;  -- 更新成绩 UPDATE scores SET score = 90 WHERE student_id = 1 AND course_id = 100;   -- 查询特定学生的信息： SELECT * FROM students WHERE student_id = 1;  --  查询特定课程的信息： SELECT * FROM courses WHERE course_id = 5;  -- 查询特定学生在特定课程上的成绩： SELECT scores.score    FROM scores    JOIN students ON scores.student_id = students.student_id    JOIN courses ON scores.course_id = courses.course_id    WHERE students.student_id = 1 AND courses.course_id = 5;  -- 查询某个班级的所有学生信息： SELECT * FROM students WHERE class_id = 1;  -- 查询某个教师的所有课程信息： SELECT courses.* FROM courses JOIN teachers ON courses.teacher_id = teachers.teacher_id WHERE teachers.teacher_name = '刘老师';