前一周寫的吧，使用中效果還不錯(cuò)。

?主要思想來自：http://www.phpobject.net/b...[url=http://www.phpobject.net/blog/read.php?49][/url]

? 這里就不多解釋原理了，直接發(fā)代碼。

? PS:這里代碼是不能直接使用的，必須結(jié)合我的一些其他庫類。應(yīng)該說思想才是最重要的，這里主要提供一種分類的思路。

復(fù)制代碼 代碼如下:

?
/**?
--??
--?表的結(jié)構(gòu)?`daxue8_category`?
--??

CREATE?TABLE?`daxue8_category`?(?
??`cid`?smallint(6)?NOT?NULL?auto_increment,?
??`pid`?smallint(6)?NOT?NULL?default?'0',?
??`level`?smallint(6)?NOT?NULL?default?'0',?
??`cname`?char(64)?NOT?NULL?default?'',?
??`lft`?smallint(6)?NOT?NULL?default?'0',?
??`rgt`?smallint(6)?NOT?NULL?default?'0',?
??`uid`?mediumint(8)?NOT?NULL?default?'0',?
??`username`?char(32)?NOT?NULL?default?'',?
??`ctime`?int(10)?NOT?NULL?default?'0',?
??`cstate`?tinyint(1)?NOT?NULL?default?'0',?
??`gnum`?mediumint(8)?NOT?NULL?default?'0',?
??`orderstyle`?smallint(3)?NOT?NULL?default?'0',?
??PRIMARY?KEY??(`cid`)?
)?TYPE=MyISAM?AUTO_INCREMENT=2?;?

--??
--?導(dǎo)出表中的數(shù)據(jù)?`daxue8_category`?
--??

INSERT?INTO?`daxue8_category`?VALUES?(1,?0,?1,?'root',?1,?2,?0,?'管理員',?1163608814,?1,?0,?0);?
*/?
class?category?
{?
????var?$module;?

????var?$tbname;?

????function?category()?
????{?
????????$this->tbname=TB_PREX.'_category';?
????????$this->module=new?module($this->tbname);?
????}?

????/**?
??????*?增加子節(jié)點(diǎn)?
??????*?@param?array?$node?待增加子節(jié)點(diǎn)的屬性?
??????*?@param?int?$pid?父節(jié)點(diǎn)的ID?
????*/?
????function?add($node,$pid){?
????????//檢查是否已經(jīng)存在該節(jié)點(diǎn)?
????????if($node_exist=$this->module->detail('where?pid='.$pid.'?and?cname=\''.$node['cname'].'\'')){?
????????????//$this->error(__FUNCTION__.'():該節(jié)點(diǎn)'.$node['cname'].'已經(jīng)存在！');?
????????????//print_r($node_exist);?
????????????return?$node_exist['cid'];?
????????}?
????????//獲取父節(jié)點(diǎn)信息?
????????$pnode=$this->get_by_cid($pid);?
????????//更新其他節(jié)點(diǎn)?
????????$this->module->query('update?`'.$this->tbname.'`?set?lft=lft+2?where?lft>'.$pnode['rgt']);?
????????$this->module->query('update?`'.$this->tbname.'`?set?rgt=rgt+2?where?rgt>='.$pnode['rgt']);?
????????//插入新節(jié)點(diǎn)?
????????$node['pid']=$pid;?
????????$node['lft']=$pnode['rgt'];?
????????$node['rgt']=$pnode['rgt']+1;?
????????$node['level']=$pnode['level']+1;//層次加一?
????????return?$this->module->add($node);?
????}?

????/**?
??????*?刪除節(jié)點(diǎn)?
??????*?@param?$cid?待刪除的節(jié)點(diǎn)的ID?
??????*?@param?$delete_childern?如果該節(jié)點(diǎn)存在子節(jié)點(diǎn)，是否強(qiáng)制刪除。設(shè)置未true，則當(dāng)存在子節(jié)點(diǎn)的時(shí)候，刪除失敗，返回false?
??????*?
????*/?
????function?delete($cid,$delete_childern=false)?
????{?
????????//獲取節(jié)點(diǎn)信息?
????????$node=$this->get_by_cid($cid);?
????????if(($this->child_num($node)>0)&&(!$delete_childern))$this->error(__FUNCTION__.'():該節(jié)點(diǎn)存在子節(jié)點(diǎn)！');?
????????//刪除該節(jié)點(diǎn)及其所有子節(jié)點(diǎn)?
????????$this->module->delete('where?lft?between?'.$node['lft'].'?and?'.$node['rgt']);?
????????//修改相應(yīng)的左右鍵值?
????????$plus=$node['rgt']-$node['lft']+1;?
????????$this->module->query('update?`'.$this->tbname.'`?set?lft=lft-'.$plus.'?where?lft>'.$node['rgt']);?
????????$this->module->query('update?`'.$this->tbname.'`?set?rgt=rgt-'.$plus.'?where?rgt>'.$node['rgt']);?
????????return?true;?
????}?

????/**?
??????*?更新一個(gè)節(jié)點(diǎn)?
??????*?@param?array?$set更新集?
??????*?@param?int?$cid?更新的節(jié)點(diǎn)的主鍵ID?
????*/?
????function?update($set,$cid){?
????????return?$this->module->update($set,'where?cid='.$cid);?
????}?

????/**?
??????*?選取節(jié)點(diǎn)及其子節(jié)點(diǎn)?
??????*?@param?int?$cid節(jié)點(diǎn)的主鍵ID?
??????*?@param?int?$deep選取深度?
????*/?
????function?select($cid,$deep=0)?
????{?
????????//獲取節(jié)點(diǎn)信息?
????????$node=$this->get_by_cid($cid);?
????????$where='where?lft?between?'.$node['lft'].'?and?'.$node['rgt'];?
????????if(!empty($deep))$where.='?and?level????????if($deep==1){?
????????????$where.='?order?by?orderstyle?desc';?
????????}else{?
????????????$where.='?order?by?lft?asc';?????????????
????????}?
????????return?$this->module->select($where);?
????}?

????/**?
??????*?獲取父節(jié)點(diǎn)路徑?
??????*?@param?int?$cid?節(jié)點(diǎn)的ID??
????*/?
????function?get_parent($cid)?
????{?
????????$node=$this->get_by_cid($cid);?
????????return?$this->module->select('where?lft='.$node['rgt'].'?order?by?lft?asc');?
????}?
????/**?
??????*?選取子節(jié)點(diǎn)?
??????*?@param?int?$cid節(jié)點(diǎn)的主鍵ID?
??????*?@param?int?$deep選取深度?
????*/?
????function?get_children($pid,$deep=0){?
????????//獲取節(jié)點(diǎn)信息?
????????$pnode=$this->get_by_cid($pid);?
????????$where='where?lft>'.$pnode['lft'].'?and?rgt????????if(!empty($deep))$where.='?and?level????????if($deep==1){?
????????????$where.='?order?by?orderstyle?desc';?
????????}else{?
????????????$where.='?order?by?lft?asc';?????????????
????????}?
????????return?$this->module->select($where);?
????}?

????/**?
??????*?獲取第deep層子節(jié)點(diǎn)?
??????*?@param?int?$cid節(jié)點(diǎn)的主鍵ID?
??????*?@param?int?$deep選取深度?
????*/?
????function?get_level_children($pid,$deep){?
????????//獲取節(jié)點(diǎn)信息?
????????$pnode=$this->get_by_cid($pid);?
????????$where='where?lft>'.$pnode['lft'].'?and?rgt????????$where.='?and?level='.($pnode['level']+$deep);?
????????$where.='?order?by?orderstyle?desc';?
????????return?$this->module->select($where);?
????}?

????/**?
??????*?獲取節(jié)點(diǎn)信息?
??????*?@param?$cid?節(jié)點(diǎn)的主鍵ID?
??????*?@return?array?$node?
????*/?
????function?get_by_cid($cid){?
????????$node=$this->module->detail('where?cid='.$cid);?
????????if(!$node)$this->error(__FUNCTION__.'():獲取節(jié)點(diǎn)'.$cid.'失?。?);?
????????return?$node;?
????}?
????/**?
??????*?獲取子節(jié)點(diǎn)的數(shù)目?
??????*?@param?array?$node?節(jié)點(diǎn)信息?
??????*?@return?num?
????*/?
????function?child_num($node){?
????????return?($node['rgt']-$node['lft']-1)/2;?
????}?
????/**?
??????*?按照層次顯示分類?
??????*?@param?int?$cid節(jié)點(diǎn)的主鍵ID?
??????*?@output?
????*/?
????function?display($cid)?
????{?
????????$nodes=$this->select($cid);?
????????foreach($nodes?as?$node){?
????????????echo?str_repeat('???',$node['level']-1).$node['cname']."\n";?
????????}?
????}?
/*-------private-----------------------------------*/?

????function?error($msg){?
????????die('ERROR?:?file?'.__FILE__.'?function?'.$msg);?
????}?
}?
?>?