如何在cakephp中进行级联

i want casecading in cakephp. I am creating city manager where I have two things zones and states as a dropdown. if i select zone then states should come according to selected zone.please help me what should be the code for model view and controller.I am new in cakephp. table for cities table is given below

CREATE TABLE IF NOT EXISTS `cities` (
`id` int(11) NOT NULL,
  `zone_id` int(11) NOT NULL,
  `state_id` int(11) NOT NULL,
  `name` varchar(255) NOT NULL,
  `code` varchar(255) NOT NULL,
  `total_sample` int(11) NOT NULL,
  `population` int(11) NOT NULL,
  `is_active` tinyint(1) NOT NULL,
  `created` datetime NOT NULL,
  `modified` datetime NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1;

--
-- Dumping data for table `cities`
--

INSERT INTO `cities` (`id`, `zone_id`, `state_id`, `name`, `code`, `total_sample`, `population`, `is_active`, `created`, `modified`) VALUES
(1, 2, 2, 'avadi', '15018', 10, 100, 1, '2016-10-03 00:00:00', '2016-10-03 00:00:00');

Please help me with code for controller, view and model.

You can do this by 2 ways

1. Using Chained javascript library. in this way you have to format dropdown. for doing this you can follow This Tutorial
2. By using Ajax request according to select Zone and State

For Option 2: Html

echo $this->Form->input('zone_id', ['options' => $zons, 'empty' => '','id'=>'zoneDropdown']);
echo $this->Form->input('state_id', ['options' => $state, 'empty' => '','id'=>'stateDropdown']);
echo $this->Form->input('city', ['options' => [], 'empty' => '','id'=>'cityDropdown']);

Ajax Script for Html

$('#zoneDropdown, #stateDropdown').on('change', function (evt) {
    ZONE = $("#zoneDropdown").val();  
    STATE = $("#stateDropdown").val();  
    $.ajax({
      type: "GET",
      url: baseURL+"cities/getCitiesOptions/"+ZONE+"/"+STATE,
      dataType: "json",
      success : function(returnData) {
          $("#cityDropdown").val(returnData);  
        }
    });
}); 

and the controller Function need to add

 Public function getCitiesOptions($zone_id=null, $state_id=null){
    $conditions = [];
    if (!empty($zone_id)) {
        $conditions['Cities.zone_id'] = $zone_id;
    }
    if (!empty($state_id)) {
        $conditions['Cities.state_id'] = $state_id;
    }

    $cities = $this->Cities->find('all',['conditions'=>$conditions])->all()->toArray();
    // make Options for dorpdown
    $html = '';
    foreach ($cities as $key => $value) {
        $html .= '<option value="'.$value['code'].'">'.$value['name'].'</option>';
    }
    return $html;
}