PHP和MySQL如何显示从数据库

Question

我不知道我将如何使用PHP MySQL的&显示我的分层数据创建我的类别和无尽的子类别分类任何子依种类？

我的PHP & MySQL的代码应该怎么看起来像将帮助了很多一个简单的例子。

MySQL表类别结构

id parent_id category 
1 0   a & w 
2 0   b & f 
3 1   c & sometimes y 
4 1   d 

Answer 1

当然，这是可能的。此代码将呈现一个<ul> <li>分层树，无论层数的

<?php 
    //Connect to mysql server 
    $cn = mysql_pconnect("server", "username", "password"); 
    mysql_select_db("database_name"); 
    $rs = mysql_query("SELECT id, parent_id, category FROM categories", $cn); 
    $childrenTree = array(); //Will store an array of children for each parent 
    $categoryNames = array(); //Will store category name for each id 
    //We fill $childrenTree and $categoryNames from database 
    while($row = mysql_fetch_array($rs)){ 
    list($id, $parent_id, $category) = $row;  
    $categoryNames[(string)$id] = $category; 
    $parent_id = (string)$parent_id; 
    if(!array_key_exists($parent_id, $childrenTree)) 
     $childrenTree[$parent_id] = array(); 
    $childrenTree[$parent_id][] = (string)$id; 
    } 

//Main recursive function. I'll asume '0' id is the root node 
function renderTree($parent = "0"){ 
    global $categoryNames; 
    global $childrenTree; 
    if($parent != "0") echo "<li> ", $categoryNames[$parent], "\n"; 
    $children = $childrenTree[$parent]; 
    if(count($children) > 0){ //If node has children 
     echo "<ul>\n"; 
     foreach($children as $child) 
      renderTree($child); 
     echo "</ul>\n"; 
    } 
    if($parent != "0") echo "</li>\n"; 
} 
renderTree(); //This renders the hierarchical tree 
?> 

为您的例子产生的HTML将是：

<ul> 
    <li> a & w 
    <ul> 
     <li> c & sometimes y </li> 
     <li> d </li> 
    </ul> 
    </li> 
    <li> b & f </li> 
</ul> 

这将在这样的浏览器渲染：

• a＆w
  • c＆有时y
  • d
• B＆F

我再说一遍，这适用于任何级别的嵌套。 希望这有助于。