PHP は、知識の質問と回答の Web サイトに質問のディスカッションと評価の機能を実装します。

CREATE TABLE `questions` (
  `id` INT(11) UNSIGNED AUTO_INCREMENT,
  `title` VARCHAR(255) NOT NULL,
  `content` TEXT NOT NULL,
  `user_id` INT(11) UNSIGNED NOT NULL,
  `created_at` DATETIME NOT NULL,
  `updated_at` DATETIME,
  PRIMARY KEY (`id`)
);

CREATE TABLE `answers` (
  `id` INT(11) UNSIGNED AUTO_INCREMENT,
  `question_id` INT(11) UNSIGNED NOT NULL,
  `content` TEXT NOT NULL,
  `user_id` INT(11) UNSIGNED NOT NULL,
  `created_at` DATETIME NOT NULL,
  `updated_at` DATETIME,
  PRIMARY KEY (`id`)
);

CREATE TABLE `ratings` (
  `id` INT(11) UNSIGNED AUTO_INCREMENT,
  `answer_id` INT(11) UNSIGNED NOT NULL,
  `user_id` INT(11) UNSIGNED NOT NULL,
  `rating` INT(11) NOT NULL,
  PRIMARY KEY (`id`)
);

<?php
// index.php

// 连接数据库
$conn = new mysqli('localhost', 'username', 'password', 'database_name');
if ($conn->connect_errno) {
    die('连接数据库失败');
}

// 获取问题列表
$result = $conn->query("SELECT * FROM questions");
if (!$result) {
    die('查询数据失败');
}

// 显示问题列表
while ($row = $result->fetch_assoc()) {
    echo '<a href="question.php?id=' . $row['id'] . '">' . $row['title'] . '</a>';
    echo '<br>';
}

// 关闭数据库连接
$conn->close();
?>

<?php
// question.php

// 连接数据库
$conn = new mysqli('localhost', 'username', 'password', 'database_name');
if ($conn->connect_errno) {
    die('连接数据库失败');
}

// 获取问题ID
$question_id = $_GET['id'];

// 获取问题信息
$result = $conn->query("SELECT * FROM questions WHERE id = $question_id");
if (!$result) {
    die('查询数据失败');
}
$question = $result->fetch_assoc();

// 获取回答列表
$result = $conn->query("SELECT * FROM answers WHERE question_id = $question_id");
if (!$result) {
    die('查询数据失败');
}

// 显示问题和回答内容
echo '<h1>' . $question['title'] . '</h1>';
echo '<p>' . $question['content'] . '</p>';

while ($row = $result->fetch_assoc()) {
    echo '<h2>回答：</h2>';
    echo '<p>' . $row['content'] . '</p>';
}

// 关闭数据库连接
$conn->close();
?>

<h2>我要回答：</h2>
<form action="answer.php" method="POST">
    <textarea name="content" rows="5" cols="50"></textarea><br>
    <input type="hidden" name="question_id" value="<?php echo $question_id; ?>">
    <input type="submit" value="提交回答">
</form>

<?php
// answer.php

// 获取回答数据
$question_id = $_POST['question_id'];
$content = $_POST['content'];

// 连接数据库
$conn = new mysqli('localhost', 'username', 'password', 'database_name');
if ($conn->connect_errno) {
    die('连接数据库失败');
}

// 插入回答数据
$stmt = $conn->prepare("INSERT INTO answers (question_id, content) VALUES (?, ?)");
$stmt->bind_param("is", $question_id, $content);
$result = $stmt->execute();
if (!$result) {
    die('插入数据失败');
}

// 关闭数据库连接
$conn->close();

// 回到问题页面
header("Location: question.php?id=$question_id");
?>

<?php
// rate.php

// 获取评价数据
$answer_id = $_GET['answer_id'];
$rating = $_GET['rating'];

// 连接数据库
$conn = new mysqli('localhost', 'username', 'password', 'database_name');
if ($conn->connect_errno) {
    die('连接数据库失败');
}

// 更新评价数据
$stmt = $conn->prepare("INSERT INTO ratings (answer_id, rating) VALUES (?, ?)");
$stmt->bind_param("ii", $answer_id, $rating);
$result = $stmt->execute();
if (!$result) {
    die('更新数据失败');
}

// 关闭数据库连接
$conn->close();

// 回到问题页面
$question_id = $_GET['question_id'];
header("Location: question.php?id=$question_id");
?>