How would I do this with xPDO?

$table = $modx->getFullTableName('products');
$result = $modx->db->update( " field1 = '$field1', field2 = '$field2'  " , $table, "parent=$parent" );

$products = $modx->getIterator('products', array('parent' => $parent));

foreach ($products as $product) {
    $product->set('field1', $field1);
    $product->set('field2', $field2);
    $product->save();
}