PHP无限级分类实现。。。。。。

1，数据库设计：

2，代码：

/**   * @author koma   * @todo   PHP无限极分类   */  $cn = mysql_connect('localhost', 'root', '') or die(mysql_error());  mysql_select_db('t', $cn) or die(mysql_error());  mysql_query('set names utf8');     /**   * 从顶层逐级向下获取子类   * @param number $pid   * @param array $lists   * @param number $deep   * @return array   */  function getLists($pid = 0, &$lists = array(), $deep = 1) {      $sql = 'SELECT * FROM category WHERE pid='.$pid;      $res = mysql_query($sql);      while ( ($row = mysql_fetch_assoc($res)) !== FALSE ) {          $row['catename'] = str_repeat('&nbsp;&nbsp;&nbsp;', $deep).'|---'.$row['catename'];          $lists[] = $row;          getLists($row['id'], $lists, ++$deep); //进入子类之前深度+1          --$deep; //从子类退出之后深度-1      }      return $lists;  }     function displayLists($pid = 0, $selectid = 1) {      $result = getLists($pid);      $str = '<select>';      foreach ( $result as $item ) {          $selected = "";          if ( $selectid == $item['id'] ) {              $selected = 'selected';          }          $str .= '<option '.$selected.'>'.$item['catename'].'</option>';      }      return $str .= '</select>';  }  /**   * 从子类开始逐级向上获取其父类   * @param number $cid   * @param array $category   * @return array:   */  function getCategory($cid, &$category = array()) {      $sql = 'SELECT * FROM category WHERE id='.$cid.' LIMIT 1';      $result = mysql_query($sql);      $row = mysql_fetch_assoc($result);      if ( $row ) {          $category[] = $row;          getCategory($row['pid'], $category);      }      krsort($category); //逆序,达到从父类到子类的效果      return $category;  }     function displayCategory($cid) {      $result = getCategory($cid);      $str = "";      foreach ( $result as $item ) {          $str .= '<a href="'.$item['id'].'">'.$item['catename'].'</a>>';      }      return substr($str, 0, strlen($str) - 1);  }     echo displayLists(0, 3);     echo displayCategory(13);

3，效果图：

来自：http://my.oschina.net/u/1156660/blog/341199