$servername = "localhost";
$username = "root";
$password = "pass";
$dbname = "db";

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    $stmt = $conn->prepare("SELECT * FROM Notes");
    $stmt->execute();

    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);

if(isset($_POST["szoveg"])){
        $query = "INSERT INTO Notes ('id', 'reg_date', 'szoveg') VALUES (NULL, CURDATE(), '".$_POST["szoveg"]."')";

        $stmt = $conn->prepare($query);
        $stmt->execute();

}