如何创建包含HTML和PHP代码混合的自定义字段并将其附加到用户

CREATE TABLE user_custom_fields (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    field_name VARCHAR(255) NOT NULL,
    field_value TEXT NOT NULL
);

<form action="save_custom_field.php" method="post">
    <input type="hidden" name="user_id" value="<?php echo $_SESSION['user_id']; ?>">
    <label for="field_name">Field Name:</label>
    <input type="text" id="field_name" name="field_name" required>
    <label for="field_value">Field Value:</label>
    <textarea id="field_value" name="field_value" required></textarea>
    <button type="submit">Save</button>
</form>

<?php
session_start();

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $user_id = $_POST['user_id'];
    $field_name = $_POST['field_name'];
    $field_value = $_POST['field_value'];

    // 连接数据库
    $conn = new mysqli('localhost', 'username', 'password', 'database');

    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }

    // 插入数据
    $sql = "INSERT INTO user_custom_fields (user_id, field_name, field_value) VALUES (?, ?, ?)";
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("iss", $user_id, $field_name, $field_value);
    $stmt->execute();

    if ($stmt->error) {
        echo "Error: " . $stmt->error;
    } else {
        echo "Custom field saved successfully!";
    }

    $stmt->close();
    $conn->close();
}
?>

<?php
// 连接数据库
$conn = new mysqli('localhost', 'username', 'password', 'database');

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$user_id = $_SESSION['user_id'];
$sql = "SELECT field_name, field_value FROM user_custom_fields WHERE user_id = ?";
$stmt = $conn->prepare($sql);
$stmt->bind_param("i", $user_id);
$stmt->execute();
$result = $stmt->get_result();

while ($row = $result->fetch_assoc()) {
    echo "<strong>" . htmlspecialchars($row['field_name']) . ":</strong> " . htmlspecialchars($row['field_value']) . "<br>";
}

$stmt->close();
$conn->close();
?>