多对多关系表mysql 创建

-- 创建学生表
CREATE TABLE students (
    student_id INT PRIMARY KEY AUTO_INCREMENT,
    student_name VARCHAR(100) NOT NULL
);

-- 创建课程表
CREATE TABLE courses (
    course_id INT PRIMARY KEY AUTO_INCREMENT,
    course_name VARCHAR(100) NOT NULL
);

-- 创建中间表
CREATE TABLE student_courses (
    student_id INT,
    course_id INT,
    PRIMARY KEY (student_id, course_id),
    FOREIGN KEY (student_id) REFERENCES students(student_id),
    FOREIGN KEY (course_id) REFERENCES courses(course_id)
);

-- 检查并修复外键约束
ALTER TABLE student_courses
ADD CONSTRAINT fk_student_courses_student
FOREIGN KEY (student_id) REFERENCES students(student_id);

ALTER TABLE student_courses
ADD CONSTRAINT fk_student_courses_course
FOREIGN KEY (course_id) REFERENCES courses(course_id);

START TRANSACTION;

INSERT INTO students (student_name) VALUES ('Alice');
INSERT INTO courses (course_name) VALUES ('Math');
INSERT INTO student_courses (student_id, course_id) VALUES (LAST_INSERT_ID(), LAST_INSERT_ID());

COMMIT;