PHP database tree traversal method_PHP tutorial

session_start();
define ('P_S', PATH_SEPARATOR);
define ('ROOT', "./");
set_include_path(ROOT .P_S .'Zend' .P_S .ROOT.get_include_path());
// Load ZEND framework
require_once ROOT.'Zend/Loader.php';
require_once 'usercheck.php';//Load access rights
Zend_Loader::loadFile('function.class.php', $dirs ='class/', $once=false);//Loading function
Zend_Loader::loadClass('Zend_Db');//Loading database class
Zend_Loader::loadClass('Zend_Config_Ini');//Loading Configuration class
$config = new Zend_Config_Ini('config.php', 'general');//Create configuration object
$db = Zend_Db::factory($config->db->adapter,$ config->db->config->toArray());//Create database object
$select=$db->select();
$select->from('ResClass' ,array('lsh','name'));
$select->where('steps = 1');
$rs=$db->fetchAll($select);
foreach ($rs as $res){
echo ' '.$res['lsh'].$res['name']."
";
Visit($res['lsh' ],1);
}
function Visit($nodeid,$stept){
global $db;
$recordset = "SELECT lsh,name FROM ResClass WHERE parent=".$nodeid; //Search all lower nodes of nodeid
$rs=$db->fetchAll($recordset);
foreach($rs as $rss){
if(!$rss)
return ; //Already a leaf node, return directly to
else{
for ($i=0;$i<4*$stept;$i++){
echo " ";
}
echo ' '.$rss['lsh'].$rss['name']."
";
Visit($rss['lsh'],$stept+1);
}
}
}
?>