SQL Prepared语句没有运行？

I had the following .php file running asynchronously through AJAX from my main page that was supposed to submit comments:

<?php
session_start();
include "dxbase.php";
$conn = new mysqli($servername, $username, $password, $dbname);



    $comment = "practice";
    $prid = 2;

    if(isset($_SESSION['user'])){

    $usera = $_SESSION['user'];


    $stmt = $conn->prepare("INSERT INTO reviews (prid, content, username) VALUES (?, ?, ?)");
    $stmt->bind_param("sss", $prid, $comment, $usera);
    $stmt->execute();
    echo "Review submitted!";
    $stmt->close();




    } else {
        echo "Oops! You need to be signed in to review products!";



    }
    $conn->close();
?>

When I ran it, it echoed back that it had submitted a comment but when I checked my database it wasn't there: DB

Why isn't it inserting?!