Insert checkbox value in mysql by using codeignite

i am novice in codeigniter. I am trying to insert multiple news that contains some check-box where its values are looped from a database. But i don't know what should code i write for this in controller & Model to insert values. can any one suggest or help me to write code?

view(content.php)

  <?php

               foreach($result as $aresult)
               {

                ?>
    <input type="checkbox" name="category_name[<?php echo $aresult->category_name; ?>]" value="<?php echo $aresult->category_name;?>" /> <?php echo $aresult->category_name;?> <br>
              <?php
                }
                  foreach($area as $aresult1)
                    {

                ?>   
                <input type="checkbox" name="category_name[<?php echo $aresult->category_name; ?>]" value="<?php echo $aresult1->category_name;?>" /> <?php echo $aresult1->category_name;?> <br>
             <?php 

                    } 
                ?>

   <tr> <td>   <input type="text" required="1" name="content_headline" tabindex="3" placeholder="Content Headline" size="80"/>  </tr> </td>
  <tr> <td>     <textarea name="content_shortdetails"  tabindex="4" maxlength="145" placeholder="Content Short Details" rows="10" cols="78"></textarea>   </tr> </td>
 <tr>
        <td>Picture</td>
        <td>
            <input type="file" name="image" tabindex="8"/>                
        </td>
    </tr>
    <tr>
        <td>Publication Status:</td>
        <td>
            <input type="radio" name="publication_status" value="1" tabindex="3"  />Publish
            <input type="radio" name="publication_status" value="0" tabindex="4"  />Unpublish
        </td>
    </tr>
   <tr>
        <td> <input type="submit" name="btn"  value="Save" tabindex="9"/></td>
    </tr>

 controller(content) :

public function savecontent()
    {    
        $data=array();
        date_default_timezone_set('Asia/Dhaka');
        $now = date("Y-m-d H:i:s");
        $data['admin_id']=$this->session->userdata('admin_id');
        $data['category_name']=$this->input->post('category_name',true);
        $data['content_headline']=$this->input->post('content_headline',true);
        $data['content_shortdetails']=$this->input->post('content_shortdetails',true);
        $data['publication_status']=$this->input->post('publication_status',true);
        $data['date_add']=$now; 
         /* -------------Image Upload---------------- */
            $this->load->library('upload');
            $config['upload_path'] = './images/news_images/';
            $config['allowed_types'] = 'gif|jpg|png|mp3';
            $config['max_size'] = '100000';
            $config['max_width'] = '';
            $config['max_height'] = '';
            $error = '';
            $udata = '';

            $this->upload->initialize($config);
            if (!$this->upload->do_upload('image')) {
                $error = array('error' => $this->upload->display_errors());
                // echo '<pre>';
                // print_r($error);
                //$this->load->view('upload_form', $error);
            } else {

                $udata = array('upload_data' => $this->upload->data());
                $data['image'] = "images/news_images/" . $udata['upload_data']['file_name'];
                $this->load->view('upload_success', $data);
            }
        $this->co_model->save_content($data);
  }

  model(co_model) :

 public function save_content($data)
{
    $this->db->insert('content',$data);
}

Database structure:

 category { cat_id(auto incr.), category_name(varchar 50) } 
 content { id(auto incr.), category_name(varchar 50), content_headline(varchar 50), shortdetails(varchar 50),  publication_status(tinyint 1), date_add(datetime), image(varchar 255) }  

in view page category_name are come from category table where i already inserted some category name and then all news are inserted in content table.
now what should i change to insert multiple row using checkbox ? when i insert one news it can be insert multiple category name(checkbox value) in multiple row in db with other value (other value not changed) .

like: category name (checkbox) =c_1, c_3, c_4 

{      content headline = something
      shortdetails = again something
      mage = pic.jpg
      publication status = 1 (publish)  }--> all this news item as same in all checked category

You will have to loop through category names because category_names is an array so it may have different values in it that's why you have to loop through each index and save the record with each index in database i have solved the issues with controller but there is in ambiguity in your view you are using category_names for two arrays which cause the problem so i have also change it.

public function savecontent()
    {  

       $check=$this->input->post('category_name',true);
       $area=$this->input->post('category_area',true);
       for($i=0; $i<sizeof($check); $i++;)
       {
        $data=array();
        date_default_timezone_set('Asia/Dhaka');
        $now = date("Y-m-d H:i:s");
        $data['admin_id']=$this->session->userdata('admin_id');
        $data['category_name']=$check[$i];
        $data['category_area']=$area[$i];
        $data['content_headline']=$this->input->post('content_headline',true);
        $data['content_shortdetails']=$this->input->post('content_shortdetails',true);
        $data['publication_status']=$this->input->post('publication_status',true);
        $data['date_add']=$now; 
         /* -------------Image Upload---------------- */
            $this->load->library('upload');
            $config['upload_path'] = './images/news_images/';
            $config['allowed_types'] = 'gif|jpg|png|mp3';
            $config['max_size'] = '100000';
            $config['max_width'] = '';
            $config['max_height'] = '';
            $error = '';
            $udata = '';

            $this->upload->initialize($config);
            if (!$this->upload->do_upload('image')) {
                $error = array('error' => $this->upload->display_errors());
                // echo '<pre>';
                // print_r($error);
                //$this->load->view('upload_form', $error);
            } else {

                $udata = array('upload_data' => $this->upload->data());
                $data['image'] = "images/news_images/" . $udata['upload_data']['file_name'];
                $this->load->view('upload_success', $data);
            }
          $this->co_model->save_content($data);
        }
        redirect('function name where you want to redirect ')
  }

}

Now your View have several changes the rest is the same loop through the code.

           foreach($result as $aresult)
               {

                ?>
    <input type="checkbox" name="category_name[<?php echo $aresult->category_name; ?>]" value="<?php echo $aresult->category_name;?>" /> <?php echo $aresult->category_name;?> <br>
              <?php
                }
                  foreach($area as $aresult1)
                    {

                ?>   
                <input type="checkbox" name="category_area[<?php echo $aresult->category_name; ?>]" value="<?php echo $aresult1->category_name;?>" /> <?php echo $aresult1->category_name;?> <br>
             <?php 

                    } 
                ?>

   <tr> <td>   <input type="text" required="1" name="content_headline" tabindex="3" placeholder="Content Headline" size="80"/>  </tr> </td>
  <tr> <td>     <textarea name="content_shortdetails"  tabindex="4" maxlength="145" placeholder="Content Short Details" rows="10" cols="78"></textarea>   </tr> </td>
 <tr>
        <td>Picture</td>
        <td>
            <input type="file" name="image" tabindex="8"/>                
        </td>
    </tr>
    <tr>
        <td>Publication Status:</td>
        <td>
            <input type="radio" name="publication_status" value="1" tabindex="3"  />Publish
            <input type="radio" name="publication_status" value="0" tabindex="4"  />Unpublish
        </td>
    </tr>
   <tr>
        <td> <input type="submit" name="btn"  value="Save" tabindex="9"/></td>
    </tr>

Change the Database structure add a column name areas where the different areas are gonna save