----------------------------------------------------------------------------------------
view
----------------------------------------------------------------------------------------


<div class="columnFull last">

    <?php $categories = $this->categoryModel->getCategories(); ?>
    <?php foreach ($categories as $category):?>
    <!-- get all categories with no parent category from the database and loop through them -->
    <div class="blockHead">
        <?php echo $category->cat_name ?>
        <!-- echo the categorys name -->
    </div>
    <div class="blockBody">
        <?php $sub_categories = $this->categoryModel->getCategories($category->cat_id); ?>
        <?php foreach ($sub_categories as $sub_categories):?>
        <!-- get all categories with the currently looping category as their parent category from the database -->
            <div class="blockHead top20">
                <?php echo $sub_categories->cat_name ?>
                <!-- echo the sub-categorys name -->
            </div>
        <?php endforeach;?>
    </div>
    <?php endforeach;?>

</div>


------------------------------------------------------------------------------------------------------
categoryModel
------------------------------------------------------------------------------------------------------

<?php
function getCategories($category = 0)
    {
    $query = $this->db->get_where('categories'​, array('cat_parent' => $category));
        return $query->result();
    }
?>