CakePHP 3 Multiple Databases

Follow the Below Instructions

Step 1 : Open config/app.php Find Datasources array and add Remote Database configuration like as -

'Datasources' => [
    'default' => [
        'className' => 'Cake\Database\Connection',
        'driver' => 'Cake\Database\Driver\Mysql',
        'persistent' => false,
        'host' => 'localhost',
        'port' => '3306',
        'username' => 'YOUR_DB_USER',
        'password' => 'YOUR_DB_PASS',
        'database' => 'YOUR_DB_NAME',
        'encoding' => 'utf8',
        'timezone' => 'UTC',
        'flags' => [],
        'cacheMetadata' => false,
        'log' => false,
        'quoteIdentifiers' => false,
        'url' => env('DATABASE_URL', null),
    ],
    'remote_db_1' => [ /*Remote Database 1*/
        'className' => 'Cake\Database\Connection',
        'driver' => 'Cake\Database\Driver\Mysql',
        'persistent' => false,
        'host' => '192.168.1.47', /*YOUR_REMOTE_SERVER_IP*/
        'port' => '3306',
        'username' => 'REMOTE_DB_USER',
        'password' => 'REMOTE_DB_PASS',
        'database' => 'REMOTE_DB_NAME',
        'encoding' => 'utf8',
        'timezone' => 'UTC',
        'flags' => [],
        'cacheMetadata' => false,
        'log' => false,
        'quoteIdentifiers' => false,
        'url' => env('DATABASE_URL', null),
    ],
   'remote_db_2' => [ /*Remote Database 2*/
        'className' => 'Cake\Database\Connection',
        'driver' => 'Cake\Database\Driver\Mysql',
        'persistent' => false,
        'host' => '192.168.1.47', /*YOUR_REMOTE_SERVER_IP*/
        'port' => '3306',
        'username' => 'REMOTE_DB_USER',
        'password' => 'REMOTE_DB_PASS',
        'database' => 'REMOTE_DB_NAME',
        'encoding' => 'utf8',
        'timezone' => 'UTC',
        'flags' => [],
        'cacheMetadata' => false,
        'log' => false,
        'quoteIdentifiers' => false,
        'url' => env('DATABASE_URL', null),
    ],

Step 2 : Now you can access Remote database in your controller like as-

use Cake\Datasource\ConnectionManager;
use \PDO;

class YourController extends AppController{
    public function getRemoteData(){
      $conn1 = ConnectionManager::get('remote_db_1'); #Remote Database 1
      $conn2 = ConnectionManager::get('remote_db_2'); #Remote Database 2
    }
}

Note: Now you can use PDO methods to Insert,Retrieve,Update

Example :

class YourController extends AppController{
    public function getRemoteData(){
      $conn1 = ConnectionManager::get('remote_db_1'); #Remote Database 1
      $sql   = "SELECT * FROM  users";
      $query = $conn1->prepare($sql);
      $query->execute();
      $result = $query->fetchAll(); #Here is the result
    }
}