Zend framework 2 model for database, separate model for each table?

I looked through the manual of Zend Framework 2 about creating model to managing operations on table. Is the class with method exchangeArray() is necessary? It's only copy data :/ Can i create one model to manage a few tables?

I created two classes:

namespace Application\Model;
use Zend\Db\Adapter\Adapter;
use Zend\Db\Adapter\AdapterAwareInterface;

    abstract class AbstractAdapterAware implements AdapterAwareInterface
    {
        protected $db;

        public function setDbAdapter(Adapter $adapter)
        {
            $this->db = $adapter;
        }
    }

and:

namespace Application\Model;

class ExampleModel extends AbstractAdapterAware
{

    public function fetchAllStudents()
    {

        $result = $this->db->query('select * from Student')->execute();

        return $result;
    }

}

I also add entries in Module.php:

'initializers' => [
                'Application\Model\Initializer' => function($instance, \Zend\ServiceManager\ServiceLocatorInterface $serviceLocator){
                    if ($instance instanceof AdapterAwareInterface)
                    {
                        $instance->setDbAdapter($serviceLocator->get('Zend\Db\Adapter\Adapter'));
                    }
                }

            ],
    'invokables' => [
        'ExampleModel' => 'Application\Model\ExampleModel'
    ],

I execute methods from model by:

$this->getServiceLocator()->get('ExampleModel')->fetchAllStudents();

You should do 2 things with your code. First, implement AdapterAwareInterface properly. Second, create an initializer which injects the adapter into your model. Consider the code below:

...

'initializers' => [
    function($instance, ServiceLocatorInterface $serviceLocator){
            if ($instance instanceof AdapterAwareInterface) {
                $instance->setDbAdapter($serviceLocator->get('Zend\Db\Adapter\Adapter'));
            }
    }
]

...

abstract class AbstractModel implements AdapterAwareInterface
{
    protected $db;

    public function setDbAdapter(Adapter $adapter)
    {
        $this->db = adapter;
    }
}

...

'invokables' => [
    'ExampleModel' => 'Application\Model\ExampleModel'
]

As you can see from above, after all, you don't need a factory for each your model. You can either register invokables or create an Abstract Factory to instantiate your models. See an example below:

...

'abstract_factories' => [
    'Application\Model\AbstractFactory'
]

...

class AbstractFactory implements AbstractFactoryInterface
{
    public function canCreateServiceWithName(ServiceLocatorInterface $serviceLocator, $name, $requestedName)
    {
        return class_exists('Application\Model\'.$requestedName);
    }

    public function createServiceWithName(\Zend\ServiceManager\ServiceLocatorInterface $serviceLocator, $name, $requestedName)
    {
        $class = 'Application\Model\'.$requestedName();

        return new $class
    }
}

Hope this helps