Anyway immediately update xml file when insert/edit in databse?

I just write code that automatic create xml file getting from databse . it look like this :

$model = new Playlists();
    $playlists = $model->getAllPlaylists();

    foreach($playlists as $playlist)
    {

        $songs = $model->getSongsByPlaylistId($playlist['playlist_id']);


        /* create a dom document with encoding utf8 */
        $dom = new DOMDocument('1.0', 'utf-8');

        $rss = $dom->createElement('rss');
        $dom->appendChild($rss);

        $version = $dom->createAttribute('version');
        $rss->appendChild($version);

        $value = $dom->createTextNode('2.0');
        $version->appendChild($value);

        $xmlns_wp = $dom->createAttribute('xmlns:media');
        $rss->appendChild($xmlns_wp);

        $value = $dom->createTextNode('http://ift.tt/W3lYmr');
        $xmlns_wp->appendChild($value);

        $xmlns_dc = $dom->createAttribute('xmlns:jwplayer');
        $rss->appendChild($xmlns_dc);

        $value = $dom->createTextNode('http://ift.tt/1nwd89e');
        $xmlns_dc->appendChild($value);

        $channel = $dom->createElement("channel");
        $channel = $rss->appendChild($channel);

        /* you should enclose the following two lines in a cicle */
        $channel->appendChild($dom->createElement('title',$playlist['playlist_title']));

        foreach($songs as $song)
        {
            $item = $dom->createElement("item");
            $item = $channel->appendChild($item);       
            $item->appendChild($dom->createElement('title',$song['song_title']));

            $mediacontent = $dom->createElement('media:content');
            $item->appendChild($mediacontent);
            $url = $dom->createAttribute('url');
            $mediacontent->appendChild($url);
            $urlvalue = $dom->createTextNode('http://ift.tt/1lax9Xx'.$song['song_ember_code'].'.m4a');
            $url->appendChild($urlvalue);

            $item->appendChild($dom->createElement('jwplayer:downloadlink','http://ift.tt/1lax9Xz'.$song['song_name']));
        }           
        /* get the xml printed */
       $dom->save("C:/xampp/htdocs/xml_playlists/".$playlist['playlist_name'].".xml");


    } 

And the result look like this :

playlist1.xml
playlist2.xml
palylist3.xml

assuming , i edited playlist2 , i want it to immediately update to playlist2.xml . I tried crontab but it must run every second to ensure my xml always new when I edited, and it will updated all my xml file . I don't want to do it this way

I wonder if there is anyway better ? Any help will be appreciate