php+mysql数据库实现无限分类的方法

//连接数据库 
$link = mysql_connect('localhost','root','') or die(mysql_error()); 
mysql_select_db('class',$link)or die(mysql_error()); 
mysql_query("set names gbk"); 
//无限分类类库 
class sortclass{ 
var $data = array(); 
var $child = array(-1=>array()); 
var $layer = array(-1=>-1); 
var $parent = array(); 
var $link; 
var $table; 
function sortclass($link, $table){ 
$this->setnode(0, -1, '顶极节点'); 
$this->link = $link; 
$this->table = $table; 
$node = array(); 
$results = mysql_query("select * from $this->table",$this->link); 
while($node = mysql_fetch_array($results)){ 
$this->setnode($node['id'],$node['f_id'],$node['name']); 
} 
} 
function setnode ($id, $parent, $value){ 
$parent = $parent?$parent:0; 
$this->data[$id] = $value; 
$this->child[$id] = array(); 
$this->child[$parent][] = $id; 
$this->parent[$id] = $parent; 
$this->layer[$id] = !isset($this->layer[$parent])? 0 : $this->layer[$parent] + 1; 
} 
function getlist (&$tree, $root= 0){ 
foreach ($this->child[$root] as $key=>$id){ 
$tree[] = $id; 
if ($this->child[$id]) $this->getlist($tree, $id); 
} 
} 
function getvalue ($id){return $this->data[$id];} 
function getlayer ($id, $space = false){ 
return $space?str_repeat($space, $this->layer[$id]):$this->layer[$id]; 
} 
function getparent ($id){return $this->parent[$id];} 
function getparents ($id){ 
while ($this->parent[$id] != -1){ 
$id = $parent[$this->layer[$id]] = $this->parent[$id]; 
} 
ksort($parent); 
reset($parent); 
return $parent; 
} 
function getchild ($id){return $this->child[$id];} 
function getchilds ($id = 0){ 
$child = array($id); 
$this->getlist($child, $id); 
return $child; 
} 
function addnode($name,$pid){ 
//echo "insert into $this->table (`f_id`,`name`) values ('$pid','$name')";exit; 
mysql_query("insert into $this->table (`f_id`,`name`) values ('$pid','$name')",$this->link); 
} 
function modnode($cid, $newname){ 
mysql_query("update $this->table set `name`='$newname' where `id` = $cid",$this->link); 
} 
function delnode($cid){ 
$allchilds = $this->getchilds($cid); 
$sql =''; 
if(emptyempty($allchilds)){ 
$sql = "delete from $this->table where `id` = $cid"; 
}else{ 
$sql = 'delete from '.$this->table.' where `id` in ('.implode(',',$allchilds).','.$cid.')'; 
} 
mysql_query($sql,$this->link); 
} 
function movenode($cid, $topid){ 
mysql_query("update $this->table set `f_id`=$topid where `id` = $cid", $this->link); 
} 
} 
//函数 
function back(){ 
echo '<script language="网页特效">window.location.href="news.class.php?"+new date().gettime();</script>'; 
exit; 
} 
//生成select 
function makeselect($array,$formname){ 
global $tree; 
$select = '<select name="'.$formname.'">'; 
foreach ($array as $id){ 
$select.='<option value="'.$id.'">'.$tree->getlayer($id, '|-').$tree->getvalue($id)."</option>"; 
} 
return $select.'</select>'; 
} 
$tree = new sortclass($link,'`p_newsclass`'); 
$op = !emptyempty($_post['op']) ? $_post['op'] : $_get['op']; 
if(!emptyempty($op)){ 
if($op=='add'){ 
$tree->addnode($_post['cname'],$_post['pid']); 
back(); 
} 
if($op=='mod'){ 
$tree->modnode($_post['cid'],$_post['cname']); 
back(); 
} 
if($op=='del'){ 
$tree->delnode($_get['cid']); 
back(); 
} 
if($op=='move'){ 
$tree->movenode($_post['who'],$_post['to']); 
back();
} 
} 
$category = $tree->getchilds(); 
?>

<style type="text/css"> 
body{font-size:12px;} 
ul{list-style:none;} 
a{cursor:pointer;} 
</style> 
<script language="javascript"> 
function $(e){return document.getelementbyid(e);} 
function mod(cid){ 
$('cid').value=cid; 
$('op').value='mod'; 
$('name').style.border='1px solid red'; 
} 
</script> 
<form action="" method="post"> 
名称:<input type="text" id="name" name="cname" /> 添加到:<?=makeselect($category,'pid')?><br /> 
<input type="hidden" id="op" name="op" value="add" /> 
<input type="hidden" id="cid" name="cid" /> 
<input type="submit" value="submit" /> 
</form> 
<h3>移动分类</h3> 
<form action="" method="post"> 
<?=makeselect($category,'who')?> gt;移动到:<?=makeselect($category,'to')?> 
<input type="hidden" id="op" name="op" value="move" /> 
<input type="submit" value="submit" /> 
</form> 
<ul> 
<?php 
foreach ($category as $id){ 
echo '<li>'.$tree->getlayer($id, '|－ ').$tree->getvalue($id).' <a href="time.php?op=del&cid='.$id.'">del</a> <a onclick="mod('.$id.')">edit</a> </li>'; 
} 
?> 
</ul>

-- phpmyadmin sql dump 
-- version 3.2.4 
-- 
-- 主机: localhost 
-- 生成日期: 2010 年 07 月 02 日 03:02 
-- 服务器版本: 5.1.41 
-- php 版本: 5.3.1 
set sql_mode="no_auto_value_on_zero"; 
 
/*!40101 set @old_character_set_client=@@character_set_client */; 
/*!40101 set @old_character_set_results=@@character_set_results */; 
/*!40101 set @old_collation_connection=@@collation_connection */; 
/*!40101 set names utf8 */; 
-- 
-- 数据库: `class` 
-- 
-- -------------------------------------------------------- 
-- 
-- 表的结构 `p_newsclass` 
-- 
create table if not exists `p_newsclass` ( 
  `id` int(7) not null auto_increment, 
  `f_id` int(7) not null, 
  `name` varchar(255) not null, 
  primary key (`id`) 
) engine=innodb  default charset=utf8 auto_increment=10 ; 
-- 
-- 转存表中的数据 `p_newsclass` 
-- 
insert into `p_newsclass` (`id`, `f_id`, `name`) values 
(3, 0, '中国'), 
(4, 3, '福建'), 
(5, 4, '龙岩市'), 
(7, 4, '厦门市'), 
(9, 5, '漳平市'); 
/*!40101 set character_set_client=@old_character_set_client */; 
/*!40101 set character_set_results=@old_character_set_results */; 
/*!40101 set collation_connection=@old_collation_connection */;