$this-db-update work but Database not change - php

Question

I am currently working on a program that uses php jquery and bootstrap, the update function, there is a an error so that database does not change but the script is running normally, Maybe somebody able to help me where is my mistake? thank you
My controller
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Subbidang extends CI_Controller {
public function index()
{
$this->load->model('model_subbidang');
$this->model_security->getsecurity();
$isi['content'] = 'Subbidang/tampilan_datasubbidang';
$isi['judul'] = 'Master';
$isi['sub_judul'] = 'Sub Bidang';
$isi['data'] = $this->db->get('tsubbidang');
$this->load->view('tampilan_home',$isi);
}
public function tambah()
{
$this->load->model('model_subbidang');
$this->model_security->getsecurity();
$isi['content'] = 'Subbidang/form_tambahsubbidang';
$isi['judul'] = 'Master';
$isi['sub_judul'] = 'Sub Bidang';
$this->load->view('tampilan_home',$isi);
}
public function simpan()
{
$this->model_security->getsecurity();
$this->load->model('model_subbidang');
$key['IDSubBidang'] = $this->input->post('kode');
$data['IDSubBidang'] = $this->input->post('kode');
$data['IDBidang'] = $this->input->post('bidang');
$data['NamaSubBidang'] = $this->input->post('subbidang');
$query = $this->db->get_where('tsubbidang',$key);
if ($query->num_rows()>0)
{
$this->db->update('tsubbidang',$key,$data);
//echo "Data Berhasil Diubah";
echo "Update";
}
else
{
$this->db->insert('tsubbidang',$data);
//xecho "Data Berhasil Disimpan";
echo 'Insert';
}
}
}
/* End of file welcome.php */
/* Location: ./application/controllers/welcome.php */
My View
<script type="text/javascript">
$(document).ready(function(){
$("#simpan").click(function(){
var string = $("#my-form").serialize();
//alert(string);
$.ajax({
type : 'POST',
url : '<?php echo site_url();?>/subbidang/simpan',
data : string,
success : function(data){
alert(data);
}
});
});
});
</script>
<form class="form-horizontal" name="my-form" id="my-form">
<div class="control-group">
<label class="control-label"bidang</label>
<div class="controls">
<select name="bidang" id="bidang">
<option value="">-Pilih-</option>
<?php
$bidang = $this->db->get('tbidang');
foreach ($bidang->result() as $row) {
?>
<option value="<?php echo $row->IDBidang;?>"><?php echo $row->Bidang;?> </option>
<?php };?>
</select>
</div>
</div>
<div class="control-group">
<label class="control-label">Kode Sub Bidang</label>
<div class="controls">
<input type="text" name="kode" id="kode" palceholder="kode" class="span3">
</div>
</div>
<div class="control-group">
<label class="control-label">Sub Bidang</label>
<div class="controls">
<input type="text" name="subbidang" id="subbidang" palceholder="Sub Bidang" class="span3">
</div>
</div>
<div class="controls">
<button type="button" name="simpan" id="simpan" class="btn btn-primary btn-small"> Simpan</button>
</div>
My Model
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Model_subbidang extends CI_model {
public function gettampildatasubbidang($key)
{
$this->db->where('IDBidang',$key);
$query = $this->db->get('tbidang');
if($query->num_rows()>0)
{
foreach ($query -> result() as $row) {
$hasil = $row->Bidang;
}
}
else
{
$hasi='';
}
return $hasil;
}
public function getlistsubbidang()
{
return $this->db->get('tbidang');
}
public function getdata($key)
{
$this->db->where('IDBidang',$key);
$hasil = $this->db->get('tBidang');
return $hasil;
}
public function getupdate($key,$data)
{
$this->db->where('IDBidang',$key);
$this->db->update('tBidang',$data);
}
public function getinsert($key,$data)
{
$this->db->insert('tBidang',$data);
}A
}
/* End of file welcome.php */
/* Location: ./application/controllers/welcome.php */
The echo work fine but the database doesnt change. The Insert function also work fine

Answer 1

You need to pass right data to update function
change
$this->db->update('tsubbidang',$key,$data);
to
$this->db->where('IDBidang', $key);
$this->db->update('tsubbidang',$data);
and Everything will be fine.
and one more thing is that you must do functionality related to database in your model not directly in controller, it is not according to the MVC structure. it destort it. and if you done everything seperetly then it is easy to understand and clear to everyone who code after you on the same.