php: updating database at end of script?

<?php

/*

  This file isn't part of PunBB.  This file is part of 'puntracker'
  a bittorrent indexer modification for PunBB.

  PunBB is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published
  by the Free Software Foundation; either version 2 of the License,
  or (at your option) any later version.

  PunBB is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  MA  02111-1307  USA

*/

// let's keep tracker within punbb
define('PUN_ROOT', './');
require_once PUN_ROOT.'include/common.php';

// comment out after debugging
// error_reporting(E_ALL);

// the scrape object
class punscrape
{
    function do_scrape()
    {

    global $db;
    
/* for debugging purposes.  comment out.
    global $complete;
    global $downloads;
    global $incomplete;
    global $matches_complete;
    global $matches_downloaded;
    global $matches_incomplete;
    global $scrape_result;
    global $scrape_url;
    global $result1;
    global $cerror;
*/
    
// let's check if the torrent(s) need(s) to be scraped. (1.5 hours)
$table = $db->prefix.'puntracker';
$result1 = $db->query("SELECT announce FROM $table 
WHERE $table.last_scrape <= NOW() - INTERVAL 1.5 HOUR");

while ($row = $db->fetch_assoc($result1)) {

// if query returns a row, scrape url
    if (isset($row['announce'])) {

$scrape_url=$row['announce'];

// create a new cURL resource
$ch = curl_init();

// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, $scrape_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);  // to return text
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 6);  // at higher values i get "PHP Fatal error:  Allowed memory size of 20971520 bytes exhausted".  you may want to adjust these values for your own needs.
curl_setopt($ch, CURLOPT_TIMEOUT, 10);

// grab URL text and set $scrape_result
$scrape_result = curl_exec($ch);

// for debugging. comment out.
$cerror = curl_error ( $ch );

// close cURL resource, and free up system resources
curl_close($ch);

switch (isset($scrape_result)) {
case TRUE:

// let's extract complete (seeds), downloaded and incomplete (peers).
preg_match("<completei\d*>", $scrape_result, $matches_complete);
preg_match("<downloadedi\d*>", $scrape_result, $matches_downloaded);
preg_match("<incompletei\d*>", $scrape_result, $matches_incomplete);

$matches_complete = implode($matches_complete);
$matches_downloaded = implode($matches_downloaded);
$matches_incomplete = implode($matches_incomplete);

$complete = ltrim($matches_complete, "completei");
$downloads = ltrim($matches_downloaded, "downloadedi");
$incomplete = ltrim($matches_incomplete, "incompletei");

// if scrape returns text update mysql
if (is_numeric($complete)) {

$complete=mysql_real_escape_string($complete);
$downloads=mysql_real_escape_string($downloads);
$incomplete=mysql_real_escape_string($incomplete);

//  update mysql.
$table = $db->prefix.'puntracker';
$query = "UPDATE $table";
$query .= " SET complete = $complete, downloads = $downloads, incomplete = $incomplete, last_scrape = NOW()";
$query .= " WHERE announce = '$scrape_url'";
$result = mysql_query($query) or die('Query failed: ' . mysql_error());

}
    break;
    
case FALSE:
    break;
}

    }}

}}

// let's run punscrape.php
$updatedb = new punscrape;
$updatedb->do_scrape();

?>