function addItemToCatalog($title, $author, $pubyear, $price){

    global $link;

    $sql = "INSERT INTO catalog (title, author, pubyear, price)
            VALUES (?, ?, ?, ?)";
    if (!$stmt = mysqli_prepare($link, $sql))
        return false;
    mysqli_stmt_bind_param($stmt, "ssii", $title, $author, $pubyear, $price);
    mysqli_stmt_execute($stmt);
    mysqli_stmt_close($stmt);
    return true;
}