在PHP中创建的RSS源不会更新

So I am trying to write a program that will send an RSS feed to every subsriber when a new data base entry is added. The code I have will give the subscriber all of the current db entries, but will not send new RSS feeds when a new item is entered. Here is my code:

<?php
header("Content-Type: application/rss+xml; charset=UTF8_general_ci"); 

//mysql connection is here


$rssfeed = '<?xml version="1.0" encoding="ISO-8859-1"?><rss version="2.0"><channel>';

//rss feed data
$rssfeed .= '<title>test</title>
            //link is here
            <description>test</description>
            <language>en-us</language>';

//items
$results = mysql_query("SELECT name FROM test");

while($row = mysql_fetch_array($results)){ //looping through items
    $rssfeed .= '<item>
                <title>' . $row['name'] . '</title>
                <description>test</description>
                //link to my website here
                <pubDate>' . date("F j, Y, g:i a") . '</pubDate>
                </item>';
}

$rssfeed .= '</channel></rss>';


echo $rssfeed;