无法发布文件php

告诉我为什么我从服务器收到404错误?在答案中不能pos ... php。 我以为问题就在眼前。我试图将与index.html放在同一目录中没有帮助。 数据库中表的名称与查询中指示的名称相对应。 谁能告诉我我的问题是什么?谢谢

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="/dist/style/app.css" />
    <title>Dictionary</title>
</head>

<body>

<div class="main-block">
    <input type="text" name="eng-text" class="eng-text"/>
    <input type="text" name="rus-text" class="rus-text"/>
    <button type="submit" class="btn-subm" name="btn-subm">Send</button>
</div>
<div class="res">

</div>


<script src="https://code.jquery.com/jquery-3.5.1.js" integrity="sha256-QWo7LDvxbWT2tbbQ97B53yJnYU3WhH/C8ycbRAkjPDc=" crossorigin="anonymous"></script>
<script src="/dist/js/app.js"></script>
</body>
</html>
function refreshData() {
    $.ajax({
        url: 'datadb.php',
        type: "POST",
        success: function (data) {
            $(".res").html(data);
        }
    });
};

$(document).ready(function () {
    $(refreshData);
    $("button.btn-subm").on("click", function () {
        console.log("send data");
        let engVal = $(".eng-text").val();
        let rusVal = $(".rus-text").val();

        $.ajax({
            url: 'db.php',
            type: "POST",
            data: {engVal: engVal, rusVal: rusVal},
        })
            .done(function () {
                $(refreshData);
            });
        $(".eng-text").val("");
        $(".rus-text").val("");

    });
});

datadb.php

<?php
    require_once("db.php");

    $query = $db->query('SELECT * FROM  `dictdb`.`dictwords`');
    while ($row = $query->fetch(PDO::FETCH_ASSOC)) {
        echo "<tr class='translater-table_item'>
             <td>" . $row['engwords'] . "</td>
             <td>" . $row['ruswords'] . "</td>
    </tr>";

}

    ?>

db.php

<?php

$dbhost = "localhost";
$dbname = "dictdb";
$username = "root";
$userpass = "";
$charset = "utf8";
$options = [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION];

$data = [
    "engVal" => trim($_POST["engVal"]),
    "rusVal" => trim($_POST["rusVal"]),
];

$db = new PDO("mysql:host=$dbhost;dbname = $dbname;charset=$charset", $username, $userpass, $options);
if (!empty(trim($_POST["engVal"])) && !empty(trim($_POST["rusVal"]))) {
    $query = "INSERT INTO `dictdb`.`dictwords`(engwords,ruswords) VALUES (:engVal, :rusVal)";
    $statement = $db->prepare($query);
    $result = $statement->execute($data);
};