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 */;