I've been trying to do this multiple times but still didn't get the answer. I have a column named closed in my database and close button in my view, whenever I click the button close, I want it to update my closed column to '0' if it is closed and '1' if it still open. below is my code in the controller, sorry I'm still new to this. 

Public function close(){
      $pvar = array();
      $pid = $this->uri->segment(1, 0);
      $iid = $this->uri->segment(2, 0);
      $pageisx = $this->uri->segment(3, 0);
      $pagei = 'Purchase Order';
      $iuser = $this->users->chkadmin();
      $gpost = $this->input->post(NULL, TRUE);
      $pvar['pageimenu'] = 'purchasing';
      $pvar['htitle'] = 'Purchase: '.$iid;
      $this->db->select('*');
      $this->db->from('po');
      $this->db->where('po.pono', $iid);
      $this->db->order_by('po.pono', 'DESC');
      $pvar['purchaseorder'] = $this->db->get()->row_array();
      if (isset($gpost['close']))
      {
        if (isset($gpost['locode'])) {
          $getlo = $gpost['locode'];
          if ($getlo == $this->session->skey) {
            foreach ($gpost['close'] as $k => $x) {
              $close = 1;
              $c['closed'] = $close;
              //$close = $this->input->post('1');
                $this->db->set('closed', 1 );
                $this->db->where('po.id', $k);
                $this->db->update('po');
              }
        redirect(base_url().'purchaseorderlist.php');
      }}}
        $pvar['css'] = '
        <link href="'.base_url().'css/manage.css" rel="stylesheet" type="text/css" />
      ';
      $pvar['pc'] = $this->load->view('purchasing/purchaseorderview', $pvar, TRUE);
      $this->load->view('home', $pvar);
      }