编辑代码

CREATE TABLE courses (
    course_id VARCHAR(10) PRIMARY KEY,
    course_name VARCHAR(100) NOT NULL,
    credits INT NOT NULL,
    hours INT NOT NULL,
    teacher_id VARCHAR(20) NOT NULL,
    course_type ENUM('必修', '选修') NOT NULL,
    description TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (teacher_id) REFERENCES users(user_id)
);