cannot insert data into database

[eluser]ubl_coder[/eluser]
Here is my model : ( mbarang.php )

Code:

<?php

if ( ! defined('BASEPATH')) exit('No direct script access allowed');

Class Mbarang extends Model {
    
    function __construct() {
        parent::Model();    
    }
    
    function simpan() {
         $data = array(
             'kode_barang'=>$this->input->post('kd_brg'),
            'nama'=>$this->input->post('nm_brg'),
            'satuan'=>$this->input->post('satuan'),
            'harga'=>$this->input->post('harga'),
            'stok'=>$this->input->post('stok')
        );
    
        $this->db->insert('barang', $data);
    }
}
?>

Any statements are incorrect?