Question

Hello Stack溢出社区。

到目前为止，我已经针对评级系统提出了两个主题，并且很高兴在您的帮助下实现了这一目标。它工作正常，只有每个人都可以投票，因此我在每次投票后都将客户的IP添加到数据库表“ votes”中。我想帮助我进行如下检查：1）如果客户已经投票通过，则不将其评分存储在数据库中。

我又如何避免插入postid，而ip是否已经存在于'votes'中呢？例如，我对ID为2的帖子投了一次票，它创建了： -ID：1 -postid：2 -ip：客户端的IP

当对同一帖子再次投票时，它会创建相同的信息，因此这是无用的，应将其屏蔽。

投票表结构：

CREATE TABLE IF NOT EXISTS `votes` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `postid` int(11) NOT NULL,
  `ip` varchar(15) DEFAULT NULL,
  `time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

已更新：/ Full Rate.php /

    <?php 

$servername = "localhost";
$username = "root";
$password = "oregon";
$dbname = "project";

    try {   
        $connection = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
        $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  

        $postid = $_POST['post_id'];
        $ip = $_SERVER['REMOTE_ADDR'];
        $sql = $connection->prepare("SELECT postid, ip FROM votes WHERE ip = :ip");
        $sql->bindParam(':ip', $ip, PDO::PARAM_STR); 
        $sql->execute();
        if($sql->rowCount() > 0){
        die("You already voted");
        }   

        $postid = $_POST['post_id'];
        $ip = $_SERVER['REMOTE_ADDR'];
        $sql = $connection->prepare("INSERT INTO votes (postid, ip) VALUES (:postid, :ip)");
        $sql->bindParam(':postid', $postid);
        $sql->bindParam(':ip', $ip);    
        $sql->execute();    

        if (isset( $_POST['slct']) && $_POST['slct'] === "1") {
            $rate = "1";
        } else if (isset( $_POST['slct']) && $_POST['slct'] === "2") {
            $rate = "2";
        } else if (isset( $_POST['slct']) && $_POST['slct'] === "3") {
            $rate = "3";
        } else if(isset( $_POST['slct']) && $_POST['slct'] === "4") {
            $rate = "4";
        } else if(isset( $_POST['slct']) && $_POST['slct'] === "5") {
            $rate = "5";
        } else {
            $rate = "0";
        }
        $id = $_POST['post_id'];
        $rating = $_POST['rate'];
        $clicks = $_POST['clicks'];
        $total_clicks = $clicks + '1';
        $max_rate = $rating + $rate;
        if($_POST['slct'] == "0") {
            $clicks = $_POST['clicks'];
            $total_clicks = $clicks + '0';
        }   

        $sql = $connection->prepare("UPDATE posts SET rate = :max_rate, clicks = :total_clicks WHERE id = :id");
        $sql->bindParam(':id', $id, PDO::PARAM_INT); 
        $sql->bindParam(':max_rate', $max_rate, PDO::PARAM_INT);
        $sql->bindParam(':total_clicks', $total_clicks, PDO::PARAM_INT);
        if ($sql->execute()) {
            header('Location: ../index.php');
        } else { 
            echo "Error updating record: " . $e->getMessage();
        }
    }
    catch(PDOException $e) {
        echo "Error: " . $e->getMessage();
    }
$connection = null;
?>

致谢。

Answer 1

您可以使用SELECT查询来检查数据库中是否已存在IP地址。

$ip = $_SERVER['REMOTE_ADDR'];
$sql = $connection->prepare("SELECT postid, ip FROM votes WHERE ip = :ip");
$sql->bindParam(':ip', $id, PDO::PARAM_INT); 
$sql->execute();
if($sql->rowCount() > 0){
  // I prefer to use the rowCount() but also a fetch will be ok for your task
    echo 'You already voted.';
} else { // do your saving tasks here }

Answer 2

在发布整个代码之前，我希望您尝试一下。如果可行，我将在第二部分中发布UPDATE查询

<?php
    $servername = "localhost";
    $username = "root";
    $password = "oregon";
    $dbname = "project";

    try {   
        $connection = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
        $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  

        $sql = $connection->prepare("SELECT * FROM votes");
        if ($sql->execute()) {
            $row_votes = $sql->fetch();
            if ($row_votes['postid'] == $_POST['post_id'] && $row_votes['ip'] == $_SERVER['REMOTE_ADDR']) {
                echo "You've already voted for this post. You cannot vote again.";
            } else {
                $sql = $connection->prepare("INSERT INTO votes (postid, ip) VALUES (:postid, :ip)");
                $sql->bindParam(':postid', $postid);
                $sql->bindParam(':ip', $ip);    
                $postid = $_POST['post_id'];
                $ip = $_SERVER['REMOTE_ADDR'];
                if ($sql->execute()) {
                    echo "INSERT was successeful";
                } else {
                    echo "INSERT was unseccessful";
                }
            }
        } else {
            echo "Could not execute query";
        }
    }
    catch(PDOException $e) {
        echo "Error: " . $e->getMessage();
    }

    $connection = null;
?>

如果“投票”表中不存在客户端IP，如何正确添加费率

2 个答案: