Creating a database-driven hierarchical Structure combined with CMenu and superfish

Tutorials

menu

Note: Please also take a look at the newer [EMenu extension](http://www.yiiframework.com/extension/emenu "Title"). This works even better that
 
the deprecated CDropDownMenu!
 
 
In this tutorial we will create a hierarchical Structure using the traditional adjacency list model. Yii's ActiveRecord paradigm makes it very easy to implement this structure via a join on itself. After this, we will use the new CMenu from yii 1.1 and implement it in conjunction with [superfish](http://users.tpg.com.au/j_birch/plugins/superfish/ "Title"), a jQuery plugin for creating menus. The [CDropDownMenu extension](http://www.yiiframework.com/extension/cdropdownmenu "Title") will help us to accomplish this task.
 
 
I will also add a tutorial using a [Nested Set](http://dev.mysql.com/tech-resources/articles/hierarchical-data.html "Title") (using the wonderful [nested set extension](http://www.yiiframework.com/extension/nestedset/ "Title")) soon.

At first, we create our SQL-Table containing our hierarchical data like this:The 'parent' field contains the id of the direct parent, while 'sort' defines, where our row gets displayed in the menu.

After that, we generate the model and a C-R-U-D interface:
 
 
~~~
 
$ php protected/yiic shell
 
Yii Interactive Tool v1.1 (based on Yii v1.1.0)
 
Please type 'help' for help. Type 'exit' to quit.
 
>> model Hierarchy
 
>> crud Hierarchy
 
~~~
 
 
When this commands run without an error using [Gii](http://www.yiiframework.com/doc/guide/1.1/en/topics.gii).
 
 
Once the model is ready, we should add two relation rules to our new created modelit: ```php public function relations()   {   return array( 'getparent' => array(self::BELONGS_TO, 'Hierarchy', 'parent'), 'childs' => array(self::HAS_MANY, 'Hierarchy', 'parent', 'order' => 'sort ASC'),   ); } ``` This reads as: the 'parent' of a row belongs to the parent-column of the same table, while we can gather the childs of a row by a relation of ourself with the `HAS_MANY` relation. We always want our childs get ordered by the column 'sort's. You can add additional relations if you want.

To test our newly created model, we need to insert some random test data:```php
$model = Hierarchy::model()->findByPk(7);
$parent = $model->getparent;
echo $parent->title;
// returns 'First Entry'$subitems = array();
if($this->childs) foreach($this->childs as $child) {
  $subitems[] = $child->getListed(); } $returnarray = array('label' => $this->headlintitle, 'url' => array('Hierarchy/view', 'id' => $this->id)); if($subitems != array())
 
        $returnarray = array_merge($returnarray, array('items' => $subitems)); return $returnarray;   }
 
} ``` We place this function in `models/Hierarchy.php` This is a recursive function (note how the function calls itself) that gathers all subchilds of an element that are available in the Database. Of course, when we run this function on our root node, we get all non-orphan childs. After that, we can use the CDropDownMenu-Widget to generate our Menu:$items[] = $model->getListed(); // note that the [] is important, otherwise CMenu will crash.

$this->widget('zii.widgets.Capplication.extensions.CDropDownMenu',array( 'items'=>$items, 'htmlOptions' => array('class' => 'sf-menu') // needed for superfish integration, see below...
 
));
 
``` to render the menu with the content of our database. This already looks nice, but we want to have a real drop-drown menu.
 
The CHtml-Menu does not contain this feature at this moment, so we use a nice jquery plugin called superfish. Thanks to jquery, this fit's really easy into our Application. After downloading and extracting superfish, just put this line in your layout file views/layouts/main.php :
 
 
~~~
 
[html]
 
<link rel="stylesheet" type="text/css" media="screen" href="superfish.css" />
 
<script type="text/javascript" src="hoverIntent.js"></script>  // <-- optional
 
<script type="text/javascript" src="superfish.js">
 
~~~
 
 
Then, we need our Script to replace the existing ul-structure with the superfish-plugin:
 
~~~
 
[html]
 
<script type="text/javascript">
 
    $(document).ready(function(){
 
        $("ul.sf-menu").superfish();
 
    });
 
</script>
 
~~~
 
Since we have defined the class of our ul-element to be 'sf-menu', this script snippet will replace our structure with the power of superfish. 
 
 
Attention: please be sure to not use this Widget inside the div id="mainmenu" of standard-generated webapps because there seems to be some css inconsistency between yii's default css and superfish's default css. Maybe this will be fixed sometime.
 
 
Note the bunch of effects and options (like drop-shadow) you can configure with superfish. in extensions/vendors/CDropDownMenu.js After this, we want our Users to be able to easily move Menu entries around. To achieve this, we will use a Drop-Down List, in which we can choose the parent of our selected element. We write this code-snippet to `views/Hierarchy/_form.php `:$data = Hierarchy::model()->findAll('parent=:parent', array('parent' => '0'));

  foreach($data as $child) { $subchilds = $child->childs; foreach($subchilds as $subchild) {     $subchild->title = $subchild->getparent->title . "|" . $subchild->title;      $data = array_merge($data, $child->childs); }   }   $rootobj = new Hierarchy;   $rootobj->id = 0;   $rootobj->title = "root level";   $root = array($rootobj);   $data = array_merge($root, $data);   if(isset($model->id) && $model->id == 1) { echo "This is the root node and can't be moved."; $model->parent = 0;   }   else { if(isset($_GET['hierarchyParent']))     echo CHtml::DropDownList('Hierarchy[parent]', $_GET['HierarchyParent'], CHtml::listData($data, 'id', 'title')); else if($update)      echo CHtml::DropDownList('Hierarchy[parent]', $model->parent, CHtml::listData($data, 'id', 'title')); else     echo CHtml::DropDownList('Hierarchy[parent]', 1, CHtml::listData($data, 'id', 'title'));   }
 
```

Note the linesif(isset($_GET['hierarchyParent']))
echo CHtml::DropDownList('Hierarchy[parent]', $_GET['HierarchyParent'], CHtml::listData($data, 'id', 'title'));

 
```

With this lines we will be able to create a "add entry to this element"-Button like this:```php
if(!Yii::app()->User->isguest)
    echo CHtml::link("Add a new element", array('Hierarchy/create', 'hierarchyParent' => $model->id));
 
``` Place this lines somewhere at `views/Hierarchy/view.php `. I hope my small tutorial was helpful for you. There are some points that can be made even better, for example someone could change the admin CGridView to be collapsable, and the elements could be moved around by drag & drop. In the next version of this Tutorial i will use the nestedset extension to achieve the Hierarchy Structure. Thank you for reading & trying, and don't hesitate to ask me when you have Questions.