XMLWriter for Google Base and Beyond

<?php
// THIS IS ABSOLUTELY ESSENTIAL - DO NOT FORGET TO SET THIS
@date_default_timezone_set("GMT");

$writer = new XMLWriter();
// Output directly to the user

$writer->openURI('php://output');
$writer->startDocument('1.0', 'UTF-8');

$writer->setIndent(4);

// declare it as an rss document that conforms to the Google Base specifications
$writer->startElement('rss');
$writer->writeAttribute('version', '2.0');
$writer->writeAttribute('xmlns:g', 'http://base.google.com/ns/1.0');
$writer->startElement("channel");
//---------------------------------------------------- replace these with you details
//$writer->writeElement('ttl', '0');
$writer->writeElement('title', 'MyCompany');
$writer->writeElement('description', 'MyCompany sells things');
$writer->writeElement('link', 'http://www.mycompany.com');
//----------------------------------------------------

//Open database connection
$dbhost = 'localhost';
$dbuser = 'username';
$dbpass = 'password';

$conn = mysql_connect($dbhost, $dbuser, $dbpass) or die ('Error connecting to mysql');

$dbname = 'my_company_shop';
mysql_select_db($dbname) or die ('Error connection to database');

//Call Products from database
$productSql = 'select * from products';
$product = mysql_query($productSql);

//----------------------------------------------------
while($products = mysql_fetch_array($product)){
    $writer->startElement('item');
    $writer->writeElement('title', $productName['products_name']);
    $writer->writeElement('g:model', $products['products_model']);
    $writer->writeElement('g:department', $productToCategoriesSetName['categories_name']);
    $writer->writeElement('description', $product['products_description']);
    $writer->writeElement('g:price', $products['products_price']);
    $writer->writeElement('g:image_link', 'http://shop.mycompany.com/images/'.$products['products_image']);
    \\ this is dependant on how you link to your products
    $writer->writeElement('link', 'http://shop.mycompany.com/product_info.php?product_id='.$products['products_id']);
    $writer->writeElement('g:condition', 'new'); \\either it is new or used, normally i would guess things are new
    $writer->writeElement('g:id', $products['products_id']);
    // End Item
    $writer->endElement();
}
//----------------------------------------------------

// End channel
$writer->endElement();
// End rss
$writer->endElement();
$writer->endDocument();
$writer->flush();