如何使用PHP開發線上問卷功能

<?php
// 连接数据库
$conn = new mysqli('localhost', 'username', 'password', 'questionnaires');
if ($conn->connect_error) {
    die("连接数据库失败：" . $conn->connect_error);
}

// 查询问卷
$sql = "SELECT * FROM surveys";
$result = $conn->query($sql);

// 显示问卷
if ($result->num_rows > 0) {
    while ($row = $result->fetch_assoc()) {
        echo "<h1>{$row['title']}</h1>";
        echo "<p>{$row['description']}</p>";
        
        // 查询问题
        $questionSql = "SELECT * FROM questions WHERE survey_id = {$row['id']}";
        $questionResult = $conn->query($questionSql);
        
        // 显示问题
        if ($questionResult->num_rows > 0) {
            while ($questionRow = $questionResult->fetch_assoc()) {
                echo "<p>{$questionRow['content']}</p>";
                
                // 根据问题类型显示不同的输入框
                if ($questionRow['type'] == 'text') {
                    echo "<input type='text' name='answer{$questionRow['id']}'><br>";
                } elseif ($questionRow['type'] == 'checkbox') {
                    echo "<input type='checkbox' name='answer{$questionRow['id']}[]' value='Option 1'>选项1<br>";
                    echo "<input type='checkbox' name='answer{$questionRow['id']}[]' value='Option 2'>选项2<br>";
                    echo "<input type='checkbox' name='answer{$questionRow['id']}[]' value='Option 3'>选项3<br>";
                } elseif ($questionRow['type'] == 'radio') {
                    echo "<input type='radio' name='answer{$questionRow['id']}' value='Option 1'>选项1<br>";
                    echo "<input type='radio' name='answer{$questionRow['id']}' value='Option 2'>选项2<br>";
                    echo "<input type='radio' name='answer{$questionRow['id']}' value='Option 3'>选项3<br>";
                }
            }
        }
        
        // 显示提交按钮
        echo "<input type='submit' value='提交'>";
    }
}

// 关闭数据库连接
$conn->close();
?>

<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 连接数据库
    $conn = new mysqli('localhost', 'username', 'password', 'questionnaires');
    if ($conn->connect_error) {
        die("连接数据库失败：" . $conn->connect_error);
    }
    
    // 处理用户答案
    foreach ($_POST as $key => $value) {
        if (strpos($key, 'answer') === 0) {
            $questionId = substr($key, 6);
            $answer = is_array($value) ? implode(", ", $value) : $value;
            
            $sql = "INSERT INTO answers (question_id, answer) VALUES ($questionId, '$answer')";
            if ($conn->query($sql) !== TRUE) {
                echo "插入答案失败：" . $conn->error;
            }
        }
    }
    
    // 关闭数据库连接
    $conn->close();
}
?>