php mysql投票系统

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "voting_system";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 开始事务
$conn->begin_transaction();

try {
    // 更新投票数
    $sql = "UPDATE options SET votes = votes + 1 WHERE option_id = ?";
    $stmt = $conn->prepare($sql);
    $stmt->bind_param("i", $option_id);
    $option_id = 1; // 假设用户选择了选项1
    $stmt->execute();

    // 提交事务
    $conn->commit();
} catch (Exception $e) {
    // 回滚事务
    $conn->rollback();
    echo "投票失败: " . $e->getMessage();
}

$stmt->close();
$conn->close();
?>

<?php
// 检查IP地址是否已经投票
$ip = $_SERVER['REMOTE_ADDR'];
$sql = "SELECT COUNT(*) as count FROM votes WHERE ip = ?";
$stmt = $conn->prepare($sql);
$stmt->bind_param("s", $ip);
$stmt->execute();
$stmt->bind_result($count);
$stmt->fetch();

if ($count >= 1) {
    echo "您已经投过票了";
} else {
    // 处理投票逻辑
}
?>