recursive tree

<?php

	error_reporting( E_ALL );
	ini_set('display_errors', 1);
	
	include 'Database.php';
	$db = new Database();

	$data = $db->getRecords();
	$newData = array();
	$tree = array();

	foreach ($data as $key => $value) {
		$newData[$value['Id']] = $value;
	}

	foreach ($newData as $key => $value) {
		if($value['parent_id'] != 0 ) {
			$tree[$value['name']] =  $newData[$value['parent_id']]['name'];
		} else {
			$tree[$value['name']] =  'null';
		}
	}

	function parseTree($tree, $root = 'null') {
	    $return = array();
	    # Traverse the tree and search for direct children of the root
	    foreach($tree as $child => $parent) {
	        # A direct child is found
	        if($parent == $root) {
	            # Remove item from tree (we don't need to traverse this again)
	            unset($tree[$child]);
	            # Append the child into result array and parse its children
	            $return[] = array(
	                'name' => $child,
	                'children' => parseTree($tree, $child)
	            );
	        }
	    }
	    return empty($return) ? null : $return;    
	}


	function printTree($tree) {
	    if(!is_null($tree) && count($tree) > 0) {
	        echo '<ul>';
	        foreach($tree as $node) {
	            echo '<li>'.$node['name'];
	            printTree($node['children']);
	            echo '</li>';
	        }
	        echo '</ul>';
	    }
	}


$result = parseTree($tree);
printTree($result);

http://stackoverflow.com/questions/2915748/convert-a-series-of-parent-child-relationships-into-a-hierarchical-tree