读取树状数据的步骤

读取树状数据的方法
读取树状数据的方法
一般在读取用“邻接列表算法”组织的数据时，需要使用递归逐层读取
或者读取数据到数组，然后用递归或非递归的方法再行处理
这里介绍一种边读边生成“树状”数组的方法，希望对你有用

mysql_connect();<br />
<br />
//测试数据<br />
$sql =<<< SQL<br />
select * from (<br />
  select '1' as id, '0' as pid, 'Food' as title<br />
  union all select '2', '1', 'Fruit'<br />
  union all select '3', '2', 'Red'<br />
  union all select '4', '3', 'Cherry'<br />
  union all select '5', '2', 'Yellow'<br />
  union all select '6', '5', 'Banana'<br />
  union all select '7', '1', 'Meat'<br />
  union all select '8', '7', 'Beef'<br />
  union all select '9', '7', 'Pork'<br />
  ) t<br />
  order by pid, id<br />
SQL;<br />
<br />
$rs = mysql_query($sql);<br />
<br />
$res = array(); //结果数组<br />
$ind = array(); //索引数组<br />
while($row = mysql_fetch_assoc($rs)) {<br />
  list($id, $pid) = array_values($row); <br />
  $ind[$id] = $row;<br />
  if(isset($ind[$pid])) $ind[$pid]['child'][$id] =& $ind[$id]; //构造索引<br />
  if($pid == 0) $res[$id] =& $ind[$id]; //转存根节点组<br />
}<br />
<br />
echo '<xmp>' . print_r($res, 1);<br />

Array
(
    [1] => Array
        (
            [id] => 1
            [pid] => 0
            [title] => Food
            [child] => Array
                (
                    [2] => Array
                        (
                            [id] => 2
                            [pid] => 1
                            [title] => Fruit
                            [child] => Array
                                (
                                    [3] => Array
                                        (