如何使用MySQL创建在线考试系统的用户答题记录表结构？

-- 创建用户表
CREATE TABLE User (
    id INT PRIMARY KEY AUTO_INCREMENT,
    username VARCHAR(255) NOT NULL,
    password VARCHAR(255) NOT NULL
);

-- 创建考试表
CREATE TABLE Exam (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(255) NOT NULL,
    time DATETIME NOT NULL
);

-- 创建试题表
CREATE TABLE Question (
    id INT PRIMARY KEY AUTO_INCREMENT,
    content TEXT NOT NULL,
    answer VARCHAR(255) NOT NULL
);

-- 创建用户参与考试表
CREATE TABLE UserParticipateExam (
    id INT PRIMARY KEY AUTO_INCREMENT,
    exam_id INT NOT NULL,
    user_id INT NOT NULL,
    FOREIGN KEY (exam_id) REFERENCES Exam(id),
    FOREIGN KEY (user_id) REFERENCES User(id)
);

-- 创建用户答题记录表
CREATE TABLE UserAnswerRecord (
    id INT PRIMARY KEY AUTO_INCREMENT,
    exam_id INT NOT NULL,
    user_id INT NOT NULL,
    question_id INT NOT NULL,
    user_answer VARCHAR(255) NOT NULL,
    FOREIGN KEY (exam_id) REFERENCES Exam(id),
    FOREIGN KEY (user_id) REFERENCES User(id),
    FOREIGN KEY (question_id) REFERENCES Question(id)
);