<?php // query.php
require_once 'test.php';
try
{
    $pdo = new PDO($attr, $user, $pass, $opts);
}
catch (PDOException $e)
{
    throw new PDOException($e->getMessage(), (int)$e->getCode());
}
$query = "SELECT * FROM grade";
$result = $pdo->query($query);

while ($row = $result->fetch())
{
    echo 'Author: ' . htmlspecialchars($row['grade']) . "<br>";
//    echo 'Title: ' . htmlspecialchars($row['title']) . "<br>";
//    echo 'Category: ' . htmlspecialchars($row['category']) . "<br>";
//    echo 'Year: ' . htmlspecialchars($row['year']) . "<br>";
//    echo 'ISBN: ' . htmlspecialchars($row['isbn']) . "<br><br>";
}
?>