Почему в базе данных происходит двойной дубль сериалов из xml?

Почему в базе данных происходит двойной дубль сериалов из xml, первый раз под категорией фильмы?

<?php
function insert($name, $desc, $year, $category_id, $rating, $poster)
{
    $mysqli = new mysqli('localhost', 'root', '', 'kinomonster');

    if (mysqli_connect_errno())
    {
        print_f("Cоединение не установлено", mysqli_connect_error());
        exit();
    }

    $mysqli->set_charset('utf8');

    $query = "INSERT INTO movie VALUES(null, '$name', '$desc', '$year', NOW(), '$category_id', '$rating', '$poster')";

    $result = false;

    if ($mysqli->query($query))
    {
        $result = true;
    }

    return $result;

}

$xml = simplexml_load_file("xml/movies.xml") or die("Cannot create object");

//echo count($xml);//
$title = null;
$title_orign = null;
$post = null;
$rating = null;
$year = null;

foreach ($xml as $movie_key => $movie)
{
    $title = $movie->title_russian;
    $title_orign = $movie->title_original;
    $year = $movie->year;

    foreach ($movie
        ->poster
        ->big
        ->attributes() as $poster_key => $poster)
    {
        $post = $poster;
    }

    if ($movie->imdb)
    {
        $rating = $movie
            ->imdb
            ->attributes() ['rating'];
    }
    else
    {
        $rating = null;
    }

    insert($title, $title_orign, $year, 1, $rating, $post);

}

$xml2 = simplexml_load_file("xml/serials.xml") or die("Cannot create object");

//echo count($xml);//
$title = null;
$title_orign = null;
$post = null;
$rating = null;
$year = null;

foreach ($xml2 as $movie_key => $movie)
{
    $title = $movie->title_russian;
    $title_orign = $movie->title_original;
    $year = $movie->year;

    foreach ($movie
        ->poster
        ->big
        ->attributes() as $poster_key => $poster)
    {
        $post = $poster;
    }

    if ($movie->imdb)
    {
        $rating = $movie
            ->imdb
            ->attributes() ['rating'];
    }
    else
    {
        $rating = null;
    }

    insert($title, $title_orign, $year, 2, $rating, $post);

}

echo "<pre>";
print_r($xml);
print_r($xml2);
echo "</pre>";

?>