Ben*_*y33 8 php mysql database tree nodes
我一直试图解决这个问题,但我没有到达任何地方.希望有人可以来救我.
我的问题是我使用邻接列表数据模型在mysql中生成我的层次结构数据.我可以将表(见下文)检索到一个多维数组中,每个项目都有一个关联数组.我想要做的是,一旦我得到这个数组,我想得到另一个数组,包含父ID(包括父项)下的所有节点(子,孙等).我只是无法锻炼如何编码tihs in PHP.
在MySQL中,我的表格如下所示:
id name parent_id
1 Electronics 0
2 Televisions 1
3 Portable Electronics 1
4 Tube 2
5 LCD 2
6 Plasma 2
7 Mp3 Players 3
8 CD Players 3
9 2 Way Radios 3
10 Flash 7
我可以使用此代码将所有行检索到关联数组中.
$r = mysql_query("SELECT * FROM test ");
$data = array();
while($row = mysql_fetch_assoc($r)) {
$data[] = $row;
}
获取结果:
Array
(
[0] => Array
(
[id] => 1
[name] => Electronics
[parent_id] => 0
)
[1] => Array
(
[id] => 2
[name] => Televisions
[parent_id] => 1
)
[2] => Array
(
[id] => 3
[name] => Portable Electronics
[parent_id] => 1
)
[3] => Array
(
[id] => 4
[name] => Tube
[parent_id] => 2
)
[4] => Array
(
[id] => 5
[name] => LCD
[parent_id] => 2
)
[5] => Array
(
[id] => 6
[name] => Plasma
[parent_id] => 2
)
[6] => Array
(
[id] => 7
[name] => Mp3 Players
[parent_id] => 3
)
[7] => Array
(
[id] => 8
[name] => CD Players
[parent_id] => 3
)
[8] => Array
(
[id] => 9
[name] => 2 Way Radios
[parent_id] => 3
)
[9] => Array
(
[id] => 10
[name] => Flash
[parent_id] => 7
)
)
有了这些结果,我想用id过滤掉它.
比方说,我想要一个ID为3的便携式电子设备下的每个节点的关联数组.(代码使用id)
它将返回一个包含id的行数组:
如果Flash有孩子,它也会返回.
因此最终结果将返回一个类似上面的数组,但只返回那些项目.
请注意:我不是在创建树结构的多维数组的函数之后(已经有了解决方案).我想构建一个函数:fetch_recursive($ id),它接收一个ID并返回所有项目那个级别和等级以下等等.
希望这可以帮助
提前致谢
Zan*_*ien 17
我之前发布过一个解决方案,用于根据您提供的输出构建多维数组,以及一种id从特定数组中获取特定元素的所有子元素的方法.我现在已经想出如何直接从输出中检索子元素(无需先完成一个buildtree()函数:
function fetch_recursive($src_arr, $currentid, $parentfound = false, $cats = array())
{
foreach($src_arr as $row)
{
if((!$parentfound && $row['id'] == $currentid) || $row['parent_id'] == $currentid)
{
$rowdata = array();
foreach($row as $k => $v)
$rowdata[$k] = $v;
$cats[] = $rowdata;
if($row['parent_id'] == $currentid)
$cats = array_merge($cats, fetch_recursive($src_arr, $row['id'], true));
}
}
return $cats;
}
要使用上面的函数,只需将输出数组传递$data给第一个参数,并且id要从第二个参数中检索子元素:
例:
$list = fetch_recursive($data, 3);
哪个应该为您提供正确的数组结构id 3(如本答案的最后一个代码框中的示例所示).
原答案:
到目前为止,我从未编写过递归函数来构建嵌套树.我确信有很多其他人都写过类似的功能,但这个功能绝对适合你:
function buildtree($src_arr, $parent_id = 0, $tree = array())
{
foreach($src_arr as $idx => $row)
{
if($row['parent_id'] == $parent_id)
{
foreach($row as $k => $v)
$tree[$row['id']][$k] = $v;
unset($src_arr[$idx]);
$tree[$row['id']]['children'] = buildtree($src_arr, $row['id']);
}
}
ksort($tree);
return $tree;
}
此函数将以邻接列表的形式递归构建树,并按升序对id进行排序.这也使id每个父/子的's成为每个信息数组的关键.
这段代码:
$r = mysql_query("SELECT * FROM test ");
$data = array();
while($row = mysql_fetch_assoc($r)) {
$data[] = $row;
}
echo '<pre>';
print_r(buildtree($data));
echo '</pre>';
会输出这样的东西:
Array
(
[1] => Array
(
[id] => 1
[name] => Electronics
[parent_id] => 0
[children] => Array
(
[2] => Array
(
[id] => 2
[name] => Televisions
[parent_id] => 1
[children] => Array
(
[4] => Array
(
[id] => 4
[name] => Tube
[parent_id] => 2
[children] => Array()
)
[5] => Array
(
[id] => 5
[name] => LCD
[parent_id] => 2
[children] => Array()
)
[6] => Array
(
[id] => 6
[name] => Plasma
[parent_id] => 2
[children] => Array()
)
)
)
[3] => Array
(
[id] => 3
[name] => Portable Electronics
[parent_id] => 1
[children] => Array
(
[7] => Array
(
[id] => 7
[name] => Mp3 Players
[parent_id] => 3
[children] => Array
(
[10] => Array
(
[id] => 10
[name] => Flash
[parent_id] => 7
[children] => Array()
)
)
)
[8] => Array
(
[id] => 8
[name] => CD Players
[parent_id] => 3
[children] => Array()
)
[9] => Array
(
[id] => 9
[name] => 2 Way Radios
[parent_id] => 3
[children] => Array()
)
)
)
)
)
)
要将特定的所有子节点id放到一维数组上,可以使用此函数:
function fetch_recursive($tree, $parent_id, $parentfound = false, $list = array())
{
foreach($tree as $k => $v)
{
if($parentfound || $k == $parent_id)
{
$rowdata = array();
foreach($v as $field => $value)
if($field != 'children')
$rowdata[$field] = $value;
$list[] = $rowdata;
if($v['children'])
$list = array_merge($list, fetch_recursive($v['children'], $parent_id, true));
}
elseif($v['children'])
$list = array_merge($list, fetch_recursive($v['children'], $parent_id));
}
return $list;
}
基于上面的buildtree()函数,假设我们想要获得id3的所有子节点:
echo '<pre>';
print_r(fetch_recursive(buildtree($a), 3));
echo '</pre>';
这将输出:
Array
(
[0] => Array
(
[id] => 3
[name] => Portable Electronics
[parent_id] => 1
)
[1] => Array
(
[id] => 7
[name] => Mp3 Players
[parent_id] => 3
)
[2] => Array
(
[id] => 10
[name] => Flash
[parent_id] => 7
)
[3] => Array
(
[id] => 8
[name] => CD Players
[parent_id] => 3
)
[4] => Array
(
[id] => 9
[name] => 2 Way Radios
[parent_id] => 3
)
)
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