PHP表单循环生成中的验证错误信息与特定表单实例关联

<code class="php"><?php
    // 假设 $user_id 通过 $_SESSION 获取
    // 假设 $connection 是数据库连接对象

    $stmt = $connection->prepare("SELECT * FROM imageposts WHERE user_id = :user_id");
    $stmt->execute([
        ':user_id' => $user_id
    ]);

    while ($row = $stmt->fetch()) {
        $db_image_filename = htmlspecialchars($row['filename'], ENT_QUOTES, 'UTF-8'); // 输出到HTML前进行转义
?>

<form method="post" enctype="multipart/form-data">
    <?php
        // 显示错误信息
        if(isset($_POST['upload-submit']) && isset($error) && isset($_POST['image-filename']) && $_POST['image-filename'] === $db_image_filename) {
            foreach($error as $msg) {
                echo "<p class='error-message'>* ERROR: " . htmlspecialchars($msg, ENT_QUOTES, 'UTF-8') . "</p>"; // 输出到HTML前进行转义
            }
        }
    ?>
    <div>
        <div class="form-row">
            <label for="upload-details-title">图片标题</label>
            <input id="upload-details-title" type="text" name="image-title">
        </div>
        <div class="form-row">
            <label for="upload-details-tags">以逗号分隔的图片标签</label>
            <textarea id="upload-details-tags" type="text" name="image-tags"></textarea>
        </div>
        <div class="form-row">
            <button name="upload-submit">完成上传</button>
        </div>
        <div class="form-row">
            <!-- 隐藏字段 -->
            <input type="hidden" name="image-filename" value="<?php echo $db_image_filename; ?>">
        </div>
    </div>
</form>

<?php } ?></code>

<code class="php"><?php
if(isset($_POST['upload-submit'])) {

    $image_title = $_POST['image-title'] ?? ''; // 使用null合并运算符，避免未定义索引警告
    $image_tags = $_POST['image-tags'] ?? '';
    $form_filename = $_POST['image-filename'] ?? '';

    $image_title = filter_var($image_title, FILTER_SANITIZE_STRING);
    $image_tags = filter_var($image_tags, FILTER_SANITIZE_STRING);
    $form_filename = filter_var($form_filename, FILTER_SANITIZE_STRING);

    $error = []; // 初始化错误数组

    // 表单验证示例
    if(empty(trim($image_title))){
        $error[] = "图片标题不能为空";
    }

    if (empty($error)) {

        try {

            $sql = "UPDATE imageposts SET
            image_title = :image_title,
            image_tags = :image_tags
            WHERE filename = :filename";

            $stmt = $connection->prepare($sql);

            $stmt->execute([
                ':image_title' => $image_title,
                ':image_tags' => $image_tags,
                ':filename' => $form_filename
            ]);

        } catch (PDOException $e) {
            echo "错误: " . $e->getMessage(); // PDO错误
        }

    }
}
?></code>