如何使用PHP和CGI实现网站的评论和点赞系统

CREATE TABLE comments (
  id INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(255) NOT NULL,
  email VARCHAR(255) NOT NULL,
  content TEXT NOT NULL,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE likes (
  id INT AUTO_INCREMENT PRIMARY KEY,
  comment_id INT NOT NULL,
  ip_address VARCHAR(255) NOT NULL,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  FOREIGN KEY (comment_id) REFERENCES comments(id)
);

<?php
// 连接数据库
$conn = mysqli_connect("localhost", "username", "password", "database");

// 查询评论数据
$query = "SELECT * FROM comments";
$result = mysqli_query($conn, $query);
$comments = mysqli_fetch_all($result, MYSQLI_ASSOC);

// 查询点赞数量
$query = "SELECT comment_id, COUNT(*) as likes_count FROM likes GROUP BY comment_id";
$result = mysqli_query($conn, $query);
$likes = mysqli_fetch_all($result, MYSQLI_ASSOC);

// 输出评论和点赞信息
foreach ($comments as $comment) {
  echo "评论者：" . $comment['name'] . "<br>";
  echo "评论时间：" . $comment['created_at'] . "<br>";
  echo "评论内容：" . $comment['content'] . "<br>";

  // 查找对应评论的点赞数量
  $likes_count = 0;
  foreach ($likes as $like) {
    if ($like['comment_id'] == $comment['id']) {
      $likes_count = $like['likes_count'];
      break;
    }
  }

  echo "点赞数量：" . $likes_count . "<br><br>";
}

// 关闭数据库连接
mysqli_close($conn);
?>

<form method="POST" action="submit.php">
  <input type="text" name="name" placeholder="姓名">
  <input type="email" name="email" placeholder="邮箱">
  <textarea name="content" placeholder="评论内容"></textarea>
  <input type="submit" value="提交评论">
</form>

<?php
// 连接数据库
$conn = mysqli_connect("localhost", "username", "password", "database");

// 接收表单数据
$name = $_POST['name'];
$email = $_POST['email'];
$content = $_POST['content'];

// 插入评论数据
$query = "INSERT INTO comments (name, email, content) VALUES ('$name', '$email', '$content')";
mysqli_query($conn, $query);

// 关闭数据库连接
mysqli_close($conn);

// 重定向到原页面
header("Location: index.php");
exit();
?>

<?php
// 连接数据库
$conn = mysqli_connect("localhost", "username", "password", "database");

// 获取用户IP地址
$ip_address = $_SERVER['REMOTE_ADDR'];

// 获取评论ID
$comment_id = $_GET['comment_id'];

// 插入点赞数据
$query = "INSERT INTO likes (comment_id, ip_address) VALUES ($comment_id, '$ip_address')";
mysqli_query($conn, $query);

// 关闭数据库连接
mysqli_close($conn);

// 重定向到原页面
header("Location: index.php");
exit();
?>

<a href="like.php?comment_id=<?php echo $comment['id']; ?>">点赞</a>