如何从数据库表创建列表视图？

Question

I'm querying a category table id, parent_id, name to generate list view of all the categories and sub-categories. What I have so far is:

• HP
  • Laptops
  • PC
• Sports
  • Sunglasses
• Food
• House

The function that I use to generate the output is:

public function get_category($parent_id = NULL)
{ 
    $query = $this->db->get_where('category', array('parent_id' => $parent_id))->result();
    $result = '';

    foreach ($query as $row)
    {
        $i = 0;

        if ($i == 0) 
        {
            $result .= '<ul>';  
        }

        $result .= '<li><a href="'.base_url().'category/edit/'.$row->id.'">' . $row->name;
        $result .= $this->get_category($row->id);
        $result .= '</li>';

        $i++;

        if ($i > 0) 
        {
            $result .= '</ul>';
        }
    }

    return $result;
}

This is what I want to achieve:

HP
HP > Laptops
HP > PC
Sports
Sports > Sunglasses
Food
House

Answer 1

Try following

public function get_category($parent_id = NULL,$level, $prev = "")
{ 
    $query = $this->db->get_where('category', array('parent_id' => $parent_id))->result();
    $result = '';

    foreach ($query as $row)
    {
       $temp = $prev;
       if($level == 0){
        $temp .= '<a href="'.base_url().'category/edit/'.$row->id.'">' . $row->name.'</a>';
       }else{
        $temp .= ' &gt; <a href="'.base_url().'category/edit/'.$row->id.'">' . $row->name.'</a>';
       }
        $result .= $temp;
        $result .= "<br />";
        $result .= $this->get_category($row->id, $level + 1, $temp);

    }

    return $result;
}

First run of this function should be

get_category(NULL, 0, "");

Here

• NULL is parent id (you can use a loop to dynamicaly pass id)
• level should be 0
• prev should be empty

Answer 2

I've created a demo according to your needs and it worked for me. I'm sharing the code below, I've done explaining in the comments wherever necessary. See if it helps you.

Controller

public function get_category($parent_id = NULL){ 

    // get the {category}, {sub_category} from the table, if {sub_category} stored in different table use {JOIN}
    $data['category'] = $this->db->get_where('category', array('parent_id' => $parent_id))->result();  

    $this->load->view('your-view', $data); 
}

View

<?php 

if(!empty($category)){ // check if {$category} has value; if not, do nothing

    $catArr = array();  // initialize array to store category id

?>

<ul>  <!-- Start ul -->

<?php 

    foreach($category as $cat){ //loop through all the {category} array

        // check if the {cat_id} already exists in array; if not, do so where {cat_id} is category id(change your value here)
        if( ! in_array( $cat->cat_id, $catArr ) ){ 

            $catArr[] = $cat->event_id;

        ?>  

        <li><?php echo $cat->cat_name; ?></li>  <!-- show {cat_name} in list -- your category name here -->

        <?php

        }

        ?>

    <!-- Show {cat_name} and {subcat_name} both -- (your values here). Give links or whatever here(your styling)-->
    <li><?php echo $cat->cat_name; ?> &gt; <?php echo $cat->subcat_name; ?></li>

    <?php

    } 

    ?>

</ul>

<?php 

} 

?>

OUTPUT

 Honda Honda > Car Honda > Bike Philips Philips > Electricals Philips > Electronics