php数据库留言板

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

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

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

<?php include 'db.php'; ?>
<!DOCTYPE html>
<html>
<head>
    <title>留言板</title>
</head>
<body>
    <h1>留言板</h1>
    <form action="submit_message.php" method="post">
        <textarea name="message"></textarea><br>
        <input type="submit" value="提交">
    </form>
    <hr>
    <?php
    $sql = "SELECT message FROM messages";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            echo "<p>" . htmlspecialchars($row["message"]) . "</p>";
        }
    } else {
        echo "还没有留言";
    }
    ?>
</body>
</html>

<?php include 'db.php'; ?>
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $message = $_POST['message'];
    $sql = "INSERT INTO messages (message) VALUES ('$message')";
    if ($conn->query($sql) === TRUE) {
        header("Location: index.php");
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}
$conn->close();
?>