php mysql聊天室系统

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(255) NOT NULL UNIQUE,
    password VARCHAR(255) NOT NULL
);

CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    message TEXT NOT NULL,
    timestamp TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY (user_id) REFERENCES users(id)
);

<?php
// 连接数据库
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "chatroom";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 处理用户登录
if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['username']) && isset($_POST['password'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];

    $sql = "SELECT * FROM users WHERE username = '$username' AND password = '$password'";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        echo "登录成功";
    } else {
        echo "用户名或密码错误";
    }
}

// 发送消息
if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['message'])) {
    $user_id = 1; // 假设当前用户ID为1
    $message = $_POST['message'];

    $sql = "INSERT INTO messages (user_id, message) VALUES ($user_id, '$message')";
    if ($conn->query($sql) === TRUE) {
        echo "消息发送成功";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

// 获取聊天记录
$sql = "SELECT * FROM messages ORDER BY timestamp DESC LIMIT 50";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "<p>" . $row["username"] . ": " . $row["message"] . " (" . $row["timestamp"] . ")</p>";
    }
} else {
    echo "没有聊天记录";
}

$conn->close();
?>