我试图从层次结构中获取MySQL数据库中的所有类别和子类别:
我的结果应该是那样的(只是示例):
- 猫A
- Sub-Cat 1
- Sub_Sub_Cat 1
- Sub_Sub_Cat 2
- Sub_Cat 2
- Cat B
- Cat C
- ...
醇>
MySQL代码:
CREATE TABLE IF NOT EXISTS `categories` (
`category_id` mediumint(8) unsigned NOT NULL AUTO_INCREMENT,
`parent_id` mediumint(8) unsigned NOT NULL DEFAULT '0' COMMENT 'for sub-categories'
PRIMARY KEY (`category_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ;
简单地说,如何使用 PHP代码进行hirarchy?
答案 0 :(得分:48)
使用邻接列表模型时,可以一次性生成结构。
取自One Pass Parent-Child Array Structure (Sep 2007; by Nate Weiner):
$refs = array();
$list = array();
$sql = "SELECT item_id, parent_id, name FROM items ORDER BY name";
/** @var $pdo \PDO */
$result = $pdo->query($sql);
foreach ($result as $row)
{
$ref = & $refs[$row['item_id']];
$ref['parent_id'] = $row['parent_id'];
$ref['name'] = $row['name'];
if ($row['parent_id'] == 0)
{
$list[$row['item_id']] = & $ref;
}
else
{
$refs[$row['parent_id']]['children'][$row['item_id']] = & $ref;
}
}
从链接文章中,这是一个用于创建输出列表的代码段。它是递归的,如果节点有子节点,它会再次调用自己来构建子树。
function toUL(array $array)
{
$html = '<ul>' . PHP_EOL;
foreach ($array as $value)
{
$html .= '<li>' . $value['name'];
if (!empty($value['children']))
{
$html .= toUL($value['children']);
}
$html .= '</li>' . PHP_EOL;
}
$html .= '</ul>' . PHP_EOL;
return $html;
}
相关问题:
答案 1 :(得分:2)
我有一个新想法,我觉得它会很好。 这个想法是这样的: 在category_parent列中,我们将插入对该节点的所有父节点的引用。
+----+----------------------+-----------------+ | id | category_name | hierarchy | +----+----------------------+-----------------+ | 1 | cat1 | 1 | +----+----------------------+-----------------+ | 2 | cat2 | 2 | +----+----------------------+-----------------+ | 3 | cat3 | 3 | +----+----------------------+-----------------+ | 4 | subcat1_1 | 1-4 | +----+----------------------+-----------------+ | 5 | subcat1_2 | 1-5 | +----+----------------------+-----------------+ | 6 | subsubcat1_1 | 1-4-6 | +----+----------------------+-----------------+ | 7 | subsubcat1_2 | 1-4-7 | +----+----------------------+-----------------+ | 8 | subsubcat1_3 | 1-4-8 | +----+----------------------+-----------------+ | 9 | subsubcat1_3_1 | 1-4-8-9 | +----+----------------------+-----------------+ | 10 | subsubcat1_3_2 | 1-4-8-10 | +----+----------------------+-----------------+ | 11 | subsubcat1_3_1_1 | 1-4-8-9-11 | +----+----------------------+-----------------+ | 12 | subsubsubcat1_3_1_1 | 1-4-8-9-12 | +----+----------------------+-----------------+ | 13 | subsubsubcat1_3_1_2 | 1-4-8-9-11-13 | +----+----------------------+-----------------+ | 14 | subsubsubcat1_2_1_3 | 1-4-8-9-11-14 | +----+----------------------+-----------------+
如果你查看我的更新表,你会发现每条记录都有一个链接到它的父母,不仅是直接的,还有所有的父母。 为了这项工作,我做了一些修改,插入:
Insert into table_name (category_name, hierarchy) values ('new_name', (concat(parent_hierarch, '-', (SELECT Auto_increment FROM information_schema.tables WHERE table_name='table_name'))))
现在让我们进行所需的查询:
1-所有子类别的汽车:
select * from table_name where hierarchy like '1-%'
2-如果你需要BLACK的所有父母,你只需输入:
select * from table_name where hierarchy = '1-4-8-9' or hierarchy = '1-4-8' or hierarchy = '1-4' or hierarchy = '1'
(您可以从php构建该查询,在&#39; - &#39; char)分割层次结构字段
3-查看具有级别和直接父级的所有类别:
select *, SUBSTR(hierarchy, 1, (LENGTH(hierarchy) - LENGTH(id) - 1)) as parent, LENGTH(hierarchy) - LENGTH(REPLACE(hierarchy, '-', '')) as level From table_name
+----+----------------------+-----------------+-----------+--------+ | id | category name | hierarchy | parent | level | +----+----------------------+-----------------+-----------+--------+ | 1 | cat1 | 1 | | 0 | +----+----------------------+-----------------+-----------+--------+ | 2 | cat2 | 2 | | 0 | +----+----------------------+-----------------+-----------+--------+ | 3 | cat3 | 3 | | 0 | +----+----------------------+-----------------+-----------+--------+ | 4 | subcat1_1 | 1-4 | 1 | 1 | +----+----------------------+-----------------+-----------+--------+ | 5 | subcat1_2 | 1-5 | 1 | 1 | +----+----------------------+-----------------+-----------+--------+ | 6 | subsubcat1_1 | 1-4-6 | 1-4 | 2 | +----+----------------------+-----------------+-----------+--------+ | 7 | subsubcat1_2 | 1-4-7 | 1-4 | 2 | +----+----------------------+-----------------+-----------+--------+ | 8 | subsubcat1_3 | 1-4-8 | 1-4 | 2 | +----+----------------------+-----------------+-----------+--------+ | 9 | subsubcat1_3_1 | 1-4-8-9 | 1-4-8 | 3 | +----+----------------------+-----------------+-----------+--------+ | 10 | subsubcat1_3_2 | 1-4-8-10 | 1-4-8 | 3 | +----+----------------------+-----------------+-----------+--------+ | 11 | subsubcat1_3_1_1 | 1-4-8-9-11 | 1-4-8-9 | 4 | +----+----------------------+-----------------+-----------+--------+ | 12 | subsubsubcat1_3_1_1 | 1-4-8-9-12 | 1-4-8-9 | 4 | +----+----------------------+-----------------+-----------+--------+ | 13 | subsubsubcat1_3_1_2 | 1-4-8-9-11-13 |1-4-8-9-11 | 5 | +----+----------------------+-----------------+-----------+--------+ | 14 | subsubsubcat1_2_1_3 | 1-4-8-9-11-14 |1-4-8-9-11 | 5 | +----+----------------------+-----------------+-----------+--------+
这是一个新想法,需要一些改进。
答案 2 :(得分:1)
@Amnon您的代码完美无缺。刚刚使用CodeIgniter测试它,它就像一个魅力。如果有人需要,这是工作代码:
<?php
function disTree($all_cats) {
$tree = array();
foreach ($all_cats as $cat)
{
$pid = $cat->parent_id;
$id = $cat->cat_id;
$name = $cat->cat_name;
// Create or add child information to the parent node
if (isset($tree[$pid]))
// a node for the parent exists
// add another child id to this parent
$tree[$pid]["children"][] = $id;
else
// create the first child to this parent
$tree[$pid] = array("children"=>array($id));
// Create or add name information for current node
if (isset($tree[$id]))
// a node for the id exists:
// set the name of current node
$tree[$id]["name"] = $name;
else
// create the current node and give it a name
$tree[$id] = array( "name"=>$name );
}
return $tree;
}
function toUL($tree, $id, $html){
$html .= '<ul>'.PHP_EOL;
if (isset($tree[$id]['name']))
$html .= '<li>' . $tree[$id]['name'];
if (isset($tree[$id]['children']))
{
$arChildren = &$tree[$id]['children'];
$len = count($arChildren);
for ($i=0; $i<$len; $i++) {
$html .= toUL($tree, $arChildren[$i], "");
}
$html .= '</li>'.PHP_EOL;
}
$html .= '</ul>'.PHP_EOL;
return $html;
}
$tree = disTree($all_cats);
// Display the tree
echo toUL($tree, 0, "");
?>
我唯一改变的是添加我自己的数组($ all_cats)。
答案 3 :(得分:1)
请尝试以下代码
//连接到mysql并选择db
$conn = mysqli_connect('localhost', 'user', 'password','database');
if( !empty($conn->connect_errno)) die("Error " . mysqli_error($conn));
//call the recursive function to print category listing
category_tree(0);
//Recursive php function
function category_tree($catid){
global $conn;
$sql = "select * from category where parent_id ='".$catid."'";
$result = $conn->query($sql);
while($row = mysqli_fetch_object($result)):
$i = 0;
if ($i == 0) echo '<ul>';
echo '<li>' . $row->cat_name;
category_tree($row->id);
echo '</li>';
$i++;
if ($i > 0) echo '</ul>';
endwhile;
}
//close the connection
mysqli_close($conn);
?>
答案 4 :(得分:0)
还有另一种达到相同效果的方法,我觉得它更容易理解(没有参考技巧)。您通过将相关信息添加到当前节点及其父节点来构建树(假设foreach迭代SQL查询中返回的行):
$tree = array();
foreach ($query->result() as $row)
{
$pid = $row->parent_id;
$id = $row->id;
$name = $row->name;
// Create or add child information to the parent node
if (isset($tree[$pid]))
// a node for the parent exists
// add another child id to this parent
$tree[$pid]["children"][] = $id;
else
// create the first child to this parent
$tree[$pid] = array("children"=>array($id));
// Create or add name information for current node
if (isset($tree[$id]))
// a node for the id exists:
// set the name of current node
$tree[$id]["name"] = $name;
else
// create the current node and give it a name
$tree[$id] = array( "name"=>$name );
}
return $tree;
并显示树:
function toUL($tree, $id, $html){
$html .= '<ul>'.PHP_EOL;
if (isset($tree[$id]['name']))
$html .= '<li>' . $tree[$id]['name'];
if (isset($tree[$id]['children']))
{
$arChildren = &$tree[$id]['children'];
$len = count($arChildren);
for ($i=0; $i<$len; $i++) {
$html .= toUL($tree, $arChildren[$i], "");
}
$html .= '</li>'.PHP_EOL;
}
$html .= '</ul>'.PHP_EOL;
return $html;
}
// Display the tree
echo toUL($tree, 0, "");