Can't update data after creating data

[rooney]

Hi all, i have some problem with create and update data
Look at this

dataSource = new kendo.data.DataSource({

   transport: {

      read: {url:"<?=base_url()?>/bank"},

      update: {url:"<?=base_url()?>/bank/update", type:"POST"},

      destroy: {url:"<?=base_url()?>/bank/destroy",type:"POST"},

      create: {url:"<?=base_url()?>/bank/create",type:"POST"},

   },

   error: function(e) {

      alert(e.responseText);

   },

   batch: true, pageSize: 25,

   schema: {

   model: {

      id: "id_bank",

      fields: {

         nama_bank: { type: "string" },

      }

   }

}

});

//kendo grid

$("#grid_bank").kendoGrid({

   dataSource: dataSource,

   editable:  "popup", height: 450, filterable: true, sortable: true, pageable: true,

   toolbar: ["create"],

   columns: [

      { field: "nama_bank",title: "Nama", filterable: true },

      { command: ["edit", "destroy"], title: " ", width: "160px" }

   ]

});

i'am using codeigniter and this script on class controller

public function index() {

   header("Content-type: application/json");

   $arr = array();

   $data=$this->bank_model->get_bank();

   foreach ($data as $hasil) {

      $arr[]=$hasil;

   }   

   print json_encode($arr);

}

     

public function create() {

   header("Content-type: application/json");

   $nama_bank = $_POST['models'][0]['nama_bank'];

   $query = "INSERT INTO bank VALUES (NULL, '$nama_bank')";

   $rs = $this->db->query($query);

   echo $query;

   if ($rs) {

      echo json_encode($rs);

   } else {

      header("HTTP/1.1 500 Internal Server Error");

   }

}

     

public function update() {

   header("Content-type: application/json");

   $id_bank = $_POST['models'][0]['id_bank'];

   $nama_bank = $_POST['models'][0]['nama_bank'];

   $query = "UPDATE bank SET nama_bank = '$nama_bank' WHERE id_bank = $id_bank";

   echo $query;

   if ($rs) {

      echo json_encode($rs);

   } else {

      header("HTTP/1.1 500 Internal Server Error");

   }

}

the problem is if process creating data is execute after that when will updating data, process always to creating data
and if in first time/page reloaded process updating is execute, that is working, but after that creating data it is problem again

Thank