How to write a join query with "two database" in cakephp - cakephp

Question

How to write a join query with two database in cakephp. Here is my code and I want to connect two db connection but I have a single Db Connection.
<?php
namespace App\Controller;
use App\Controller\AppController;
use Cake\Datasource\ConnectionManager;
use src\Model\Table\classScheduleDbConnTable;
class TimeTableController extends AppController {
public function index() {
$jpDB = ConnectionManager::get('default');
$ClsDB = ConnectionManager::get('test');
$result = $ClsDB->execute('SELECT * FROM t_class_schedule')->fetchAll('assoc');
$data=array();
foreach ($result as $key => $value) {
$data[$key]['id'] = $value['id'];
$dates = date("Y-m-d", strtotime($value['classDate']));
$data[$key]['fromTime'] = $value['fromTime'];
$data[$key]['toTime'] = $value['toTime'];
$data[$key]['keyWord'] = $value['keyWord'];
$data[$key]['classDate'] = $dates;
}
$this->set('datas',$data);
}
}

Answer 1

I don't believe you can just "connect" two ConnectionManagers in this way.
You probably have two options:
Option A - Specify the database name statically as part of the Table's initialization per the example in this post:
public function initialize(array $config)
{
$this->table('databaseName.tableName');
// ...
}
Option B - Specify an alternative connection & Lazy Load
You can specify an alternative connection names for a specific Model at the Table level:
class ClassSchedule extends Table
{
public static function defaultConnectionName() {
return 'test';
}
}
Note that this can't be used in a join on other Tables using the default connection. You'll instead have to "lazy load" associated data manually. As a general example (I don't know what your associations are, just a random example):
$student->class_schedules = TableRegistry::get('ClassSchedules')->find()
->where(['student_id'=>$student-id])
->toArray();