Can't edit values to database with set_relation_n_n

Hello, I have problem with editing values in my database.

I have 3 tables, 'tbl_perawat', 'tbl_ruangan', and 'perawatruangan'.

'tbl_perawat' structure: http://prntscr.com/8xckn2

'tbl_ruangan' structure: http://prntscr.com/8xckyl

'perawatruangan' structure: http://prntscr.com/8xcl3v and relation: http://prntscr.com/8xcl85

Here's my controller for 'perawatruangan':

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
 
class PerawatRuangan extends CI_Controller {
 
    function __construct()
    {
        parent::__construct();
 
        /* Standard Libraries of codeigniter are required */
        $this->load->database();
        $this->load->helper('url');
        /* ------------------ */ 

        $this->load->library('grocery_CRUD');
 
    }

    public function index()
    {
        //Inisialisasi
        $crud = new grocery_CRUD();
        $crud->set_subject('Perawat Ruangan');
        $crud->set_table('tbl_ruangan');
        $crud->set_theme('datatables');

        //Label Fields
        $crud->display_as('kdRuangan','Kode Ruangan');
        $crud->display_as('namaRuangan','Nama Ruangan');
        $crud->display_as('detail','Perawat');
        $crud->columns('kdRuangan','detail');
        $crud->fields('kdRuangan','detail');
        $crud->unset_add();
        $crud->unset_delete();

        //Kolom Input dan Callbacks
        $crud->set_relation_n_n('detail', 'perawatruangan', 'tbl_perawat', 'kdRuangan', 'idPerawat', 'namaPerawat','prioritas');

        //Aturan Pengisian Form
        $crud->set_language('indonesian');

        //Cetak Tabel
        $output = $crud->render();
 
        $this->_example_output($output);        
    }

    function _example_output($output = null)
    {
        $this->load->view('vperawatruangan.php',$output);    
    }
 }

When I try to edit, adding or deleting namaPerawat, I can't update. But when I click first 'Remove All' before I try to adding or deleting, it works. Any solution how to add/delete without click 'Remove All' first?

If I add other values, it replace old values with the new ones in database, but it has error noticed in edit form.

=================================================

Problem solved.

Can't edit values to database with set_relation_n_n

Elra Ghifary