How to insert multiple array into one row database on codeigniter?

After so many trial and error and searching many resource. Finally i came to my own solution. Hope i can help others with my code. Please feel free to add another solution for this problem...

View Page for Input Data (form-input.php)

<?php echo form_open('#', array('class'=>'form') ); ?>

   <?php 
       $i = 0;
       if ($valuation != NULL):
   ?>

       // Form field will looping through this as many as foreach result
       <?php foreach ($valuation as $value): ?>

           <input type="text" name="variable[<?php echo $x; >?]" value="<?php echo $value->category; ?>" readonly="readonly">
           <select name="score[<?php echo $x; ?>]">
               <option value=""> — Choose Score — </option>
               <option value="0"> 0 </option>
               <option value="1"> 1 </option>
               <option value="2"> 2 </option>
               <option value="3"> 3 </option>
           </select>
           <textarea name="desc[<?php echo $x; ?>]" rows="5" required="required"></textarea>

       <?php
           $x++;
           endforeach;
       ?>

   <?php
        else:
            echo 'No input field generate';
        endif;
   ?>

<?php
    echo form_button(array('name'=>'submit', 'type'=>'submit', 'content'=>'Save') );
    echo form_close();
?>

The Controller (Collection.php)

public function save()
{
   // get collection ID from URL
   $collectionID = $this->input->get('coll_id');

   //Form Validation
   $this->form_validation->set_rules('variable[]', 'Variable', 'required', array('required'=>'%s cannot empty'));
   $this->form_validation->set_rules('score[]', 'Score', 'required', array('required'=>'%s cannot empty'));
   $this->form_validation->set_rules('desc[]', 'Description', 'required', array('required'=>'%s cannot empty'));

   if ($this->form_validation->run() == FALSE)
   {
       $data = array(
           'page_title' => 'Add Significance Data for ' . $collectionID,
           'valuation' => $this->significance_db->get_value_list()
       );
       $this->load->view('form-input', $data);
   }
   else
   {
       $count = count($this->input->post('variable'));
       for ($i=0; $i<$count; $i++)
       {
           $json_data[] = array(
               'variable' => $this->input->post('variable')[$i],
               'score' => $this->input->post('score')[$i],
               'description' => $this->input->post('desc')[$i]
           );
       }
       $json_encode_data = json_encode($json_data);

       $db_data = array(
           'collection_ID' => $collectionID,
           'valuation' => $json_encode_data,
           'post_by' => $this->session->userdata('user_ID'),
           'post_datetime' => get_datetime_format()
       );

       if ($this->significance_db->save_data($db_data) == TRUE)
       {
          'some function here if TRUE';
       }
       else
       {
          'some function here if FALSE';
       }
   }
}

Model (significance_db.php)

function save_data($db_data)
{
     $this->db->insert('table_name', $db_data);
     if ($this->db->affected_rows() > 0)
     {
         return TRUE;
     }
     else
     {
         return FALSE;
     }
}

So that is how to inserting data to my database table. It will create one row with the array content (generate with json_encode) in the valuation column.

Another code below is how to view this data. I will show the example of my Controller, Model, and View.

Controller (inside the Collection.php too)

public function show()
{
    //get collection ID from URL
    $collectionID = $this->input->get('coll_id');

    $data = array(
        'page_title' => 'Show Significance Data from ' . $collectionID,
        'significance' => $this->significance_db->get_significance_data($collectionID)
    );
    $this->load->view('view-page', $data);
}

View Page for Diplaying Data (view-page.php)

<?php if ($significance != NULL: ?>

    <div class="row">
        <div class="col-sm-12">
            <div class="card">
                <div class="card-body">

                    <?php foreach ($significance as $value): ?>

                        <?php
                            $data = json_decode($value->valuation); 
                            $count = count($data);
                        ?>

                        <?php for ($i=0; $i<$count; $i++): ?>

                            <ul class="list-inline">
                                <li class="list-inline-item"><?php echo $data[$i]->variable; ?></li>
                                <li class="list-inline-item"><?php echo $data[$i]->score; ?></li>
                                <li class="list-inline-item"><?php echo $data[$i]->description; ?></li>
                            </ul>

                        <?php endfor; ?>

                    <?php endforeach; ?>

                </div>
            </div>
        </div>
    </div>

<?php else: ?>

    <strong> No Data Result. </strong>

<?php endif; ?>

If you want to know the data from json_decode($value->valuation) you can check with print_r($data) or whatever the script you prefer to showing array.

Finally. Hope this can help others. If anyone have another method which create same function/method like this, please feel free to comment or add another method.