Gerador de Sitemaps PHP e MySQL

<?php
/**
 * @author  Franco Salcedo
 * [MENTION=3037]Link[/MENTION]    Generador de sitemaps miltiples :)
 */

error_reporting(E_ALL);
set_time_limit(0);

    const _CONF_MYSQL_DB    = 'letras',
          _CONF_MYSQL_HOST  = 'localhost',
          _CONF_MYSQL_USER  = 'root',
          _CONF_MYSQL_PASS  = '',

          PREFIJO = 'siteamps_';

    try {
        $db = new PDO("mysql:dbname=" . _CONF_MYSQL_DB . ";host=" . _CONF_MYSQL_HOST, _CONF_MYSQL_USER, _CONF_MYSQL_PASS);
        $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    }
    catch (PDOException $e) {
        echo "Error de Conexion: " . $e->getMessage();
        die;
    }

// una funcion seo que pueden utilizar.
function seeo($string, $slug = '-', $maxlength = 0){
    $seo = strtolower(trim(preg_replace('~[^0-9a-z]+~i', $slug, html_entity_decode(preg_replace('~&([a-z]{1,2})(?:acute|cedil|circ|grave|lig|orn|ring|slash|th|tilde|uml);~i', '$1', htmlentities($string, ENT_QUOTES, 'UTF-8')), ENT_QUOTES, 'UTF-8')), $slug));
    $seo = (!empty($maxlength)) ? substr($seo, 0, strrpos(substr($seo, 0, $maxlength), $slug)) : substr($seo, 0, 50);
    return $seo;
}

function saveFile($name, $buffer){
    // acomodar la carpeta donde se ha de generar
    $file = fopen("sitemaps/$name.xml", "w+");
    fwrite($file, $buffer);
    fclose($file);
}


// acomodar la consulta segun sus necediades
$sql = $db->prepare("select * from temas");
$sql->execute();

$actua   = 0;
$mem     = '';
$numfile = 1;

while ($p = $sql->fetchObject()) {
    if ($actua == 20000) {
        $actua = 0;
        $in    = '<?xml version="1.0" encoding="utf-8"?><urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">';
        $fi    = '</urlset>';
        $file  =  PREFIJO . $numfile;
        saveFile($file, $in . $mem . $fi);
        $mem = '';
        $numfile++;
    }

    // En esta linea configurar como deben de ir sus urls
    $mem .= '<url><loc>[url]http://www.web.com/[/url]' . $p->soy_un_campo . '/</loc></url>';
    $actua++;
}

    echo "Se generaron $numfile Sitemaps";
?>