用mysql创建数据库留言板

CREATE DATABASE message_board;

USE message_board;

CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) NOT NULL,
    content TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "message_board";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

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

// 插入留言
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $username = $_POST['username'];
    $content = $_POST['content'];
    $sql = "INSERT INTO messages (username, content) VALUES ('$username', '$content')";
    if ($conn->query($sql) === TRUE) {
        echo "留言成功";
    } else {
        echo "错误: " . $sql . "<br>" . $conn->error;
    }
}

// 查询留言
$sql = "SELECT * FROM messages";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "用户名: " . $row["username"]. " - 内容: " . $row["content"]. " - 时间: " . $row["created_at"]. "<br>";
    }
} else {
    echo "没有留言";
}

$conn->close();
?>