Create multi-level category using recursive function in Yii

Creating multi-level category system with PHP & Yii (MVC Framework) in not just a simple undertaking.
Many Developer usage different type to handle this specific. They may possibly create 3 tables for initial level, subsequent level as well as 3rd level category (parent, sub category as well as sub sub cateogry).
The best method to acquire multi-level category using recursive function.
With this, let us build a database table i.e category. as shown below

At first, we create our SQL-Table

CREATE TABLE `menus` ( `id` int(11) NOT NULL, `name`

varchar(150) CHARACTER SET utf8 NOT NULL, `link` varchar(500)

CHARACTER SET utf8 NOT NULL, `parent_id` int(11) NOT NULL, `class_style`

varchar(100) CHARACTER SET utf8 NOT NULL, `order_by` int(11) NOT NULL,

`status` int(11) NOT NULL DEFAULT '0' COMMENT '0-->active,1-->Inactive', `menu_type` int(11) NOT NULL DEFAULT '0' COMMENT '0-->admin,1-->Telicaller', `created` date NOT NULL )

ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; 

1. 
   

Firstly Create database like attachment, with the help of phpmyadmin
For example I have a table like this

Create Function in models

function getRootCategory($cur_cat='') {

$sql='select id, course_name, parent_id from course where parent_id="0" and status=0'; $command=Yii::app()->db->createCommand($sql);

$return =$command->queryAll();

foreach($return as $rootCat){

if ($rootCat['id']==$cur_cat){

$test= 'selected=selected'; }else{

$test=''; }

$id=$rootCat['id'];

echo "".$rootCat['course_name'].'';

$this->sub_cat($rootCat['id'] , '', $cur_cat ); } }

function sub_cat($parentID=0, $space='',$cur_cat ) {

$sql="select id, course_name, parent_id from course where parent_id='$parentID' and status=0";

$command=Yii::app()->db->createCommand($sql);

$return =$command->queryAll();

$count=count($return);

if($parentID==0){ $space=''; }else{ $space .=" - "; }

if($count > 0){

foreach($return as $subcat){

if ($subcat['id']==$cur_cat){$test='selected=selected';}else{$test='';}

$ids=$subcat['id'];

echo "".$space.$subcat['course_name'].'';

$this->sub_cat($subcat['id'],$space, $cur_cat ); } } }

Now create this code in view/file.php
<?php
echo ‘<select id=”parent_id” class=”select” name=”Course[parent_id]” >’;
echo “<option value=’0′  >–Select Exam–</option>”;
echo Course::model()->getRootCategory($model->parent_id);
// ($model->parent_id) means selected text box
echo ‘</select>’; ?>