我有一个游戏，你可以提交你的得分到一个数据库，但由于某种原因，提交不断被触发两次。每个条目都加倍。我在这里看到过类似的问题，解决方法是最后的if/else检查，但我没有看到问题。
是我的php代码在复制条目还是我的游戏应用程序？

<?php

$servername = "xxx";
$username = "xxx";
$password = "xxx";
$dbname = "xxx";
$port = "xxx";

$link = mysqli_connect($servername, $username, $password, $dbname, $port);

// Security
$playerInitials = mysqli_real_escape_string($link,$_REQUEST['initials']);
$playerEmail = mysqli_real_escape_string($link,$_REQUEST['email']);
$playerScore = mysqli_real_escape_string($link,$_REQUEST['score']);

// Convert Initials to Upper Case
$playerInitialsUC = strtoupper($playerInitials);

$sql = "INSERT INTO xmas (initials, email, score)
VALUES ('$playerInitialsUC', '$playerEmail', '$playerScore')";

if(mysqli_query($link, $sql)){
    echo "Records added successfully.";
} else{
    echo "ERROR: " . mysqli_error($link);
}

mysqli_close($link);

?>