public static function getTagCategoriesByScheme($db, $app_root, $scheme)
{
$cats = new Dase_Atom_Categories();
$cats->setScheme('http://daseproject.org/category/' . $scheme);
$prefix = $db->table_prefix;
$sql = "\n\t\t\tSELECT term, label \n\t\t\tFROM {$prefix}tag_category \n\t\t\tWHERE scheme = ?\n\t\t\tGROUP BY term, label\n\t\t\tORDER BY label\n\t\t\t";
$dbh = $db->getDbh();
$sth = $dbh->prepare($sql);
$sth->execute(array($scheme));
foreach ($sth->fetchAll() as $row) {
$cats->addCategory($row['term'], '', $row['label']);
}
return $cats->asXml();
}
