数据库学生选课系统

-- 创建学生表
CREATE TABLE students (
    student_id INT PRIMARY KEY,
    student_name VARCHAR(100),
    student_major VARCHAR(100)
);

-- 创建课程表
CREATE TABLE courses (
    course_id INT PRIMARY KEY,
    course_name VARCHAR(100),
    course_credits INT
);

-- 创建选课记录表
CREATE TABLE enrollments (
    enrollment_id INT PRIMARY KEY,
    student_id INT,
    course_id INT,
    FOREIGN KEY (student_id) REFERENCES students(student_id),
    FOREIGN KEY (course_id) REFERENCES courses(course_id)
);

-- 插入示例数据
INSERT INTO students (student_id, student_name, student_major) VALUES
(1, 'Alice', 'Computer Science'),
(2, 'Bob', 'Mathematics');

INSERT INTO courses (course_id, course_name, course_credits) VALUES
(101, 'Introduction to Programming', 3),
(102, 'Calculus I', 4);

INSERT INTO enrollments (enrollment_id, student_id, course_id) VALUES
(1, 1, 101),
(2, 2, 102);

-- 查询学生选课信息
SELECT s.student_name, c.course_name
FROM students s
JOIN enrollments e ON s.student_id = e.student_id
JOIN courses c ON e.course_id = c.course_id;