留言板mysql数据库

-- 创建用户表
CREATE TABLE Users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    password VARCHAR(255) NOT NULL,
    email VARCHAR(100)
);

-- 创建留言表
CREATE TABLE Messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    content TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (user_id) REFERENCES Users(id)
);

-- 创建回复表
CREATE TABLE Replies (
    id INT AUTO_INCREMENT PRIMARY KEY,
    message_id INT NOT NULL,
    user_id INT NOT NULL,
    content TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (message_id) REFERENCES Messages(id),
    FOREIGN KEY (user_id) REFERENCES Users(id)
);

-- 插入用户数据
INSERT INTO Users (username, password, email) VALUES ('user1', 'password1', 'user1@example.com');

-- 插入留言数据
INSERT INTO Messages (user_id, content) VALUES (1, 'Hello, this is a test message.');

-- 插入回复数据
INSERT INTO Replies (message_id, user_id, content) VALUES (1, 1, 'This is a reply to the test message.');