Can I use ORM without connecting entity to a database table - entity-framework

Question

I have an Entity that pulls it's data from a REST web service. To keep thing consistent with the entities in my app that pull data from the database I have used ORM and overridden the find functions in the repository.
My problem is that ORM seems to demand a database table. When I run doctrine:schema:update it moans about needing an index for the entity then when I add one it creates me a table for the entity. I guess this will be a problem in the future as ORM will want to query the database and not the web service.
So... am I doing this wrong?
1, If I continue to use ORM how can I get it to stop needing the database table for a single entity.
2, If I forget ORM where do I put my data loading functions? Can I connect the entity to a repository without using ORM?

Answer 1

So... am I doing this wrong?
Yes. It doesn't make sense to use the ORM interfaces if you don't really want to use an ORM.
I think the best approach is NOT to think about implementation details at all. Introduce your own interfaces for repositories:
interface Products
{
/**
* #param string $slug
*
* #return Product[]
*/
public function findBySlug($slug);
}
interface Orders
{
/**
* #param Product $product
*
* #return Order[]
*/
public function findProductOrders(Product $product);
}
And implement them with either an ORM:
class DoctrineProducts implements Products
{
private $em;
public function __construct(EntityManager $em)
{
$this->em = $em;
}
public function findBySlug($slug)
{
return $this->em->createQueryBuilder()
->select()
// ...
}
}
or a Rest client:
class RestOrders implements Orders
{
private $httpClient;
public function __construct(HttpClient $httpClient)
{
$this->httpClient = $httpClient;
}
public function findProductOrders(Product $product)
{
$orders = $this->httpClient->get(sprintf('/product/%d/orders', $product->getId()));
$orders = $this->hydrateResponseToOrdersInSomeWay($orders);
return $orders;
}
}
You can even make some methods use the http client and some use the database in a single repository.
Register your repositories as services and use them rather then calling Doctrine::getRepository() directly:
services:
repository.orders:
class: DoctrineOrders
arguments:
- #doctrine.orm.entity_manager
Always rely on your repository interfaces and never on a specific implementation. In other words, always use a repository interface type hint:
class DefaultController
{
private $orders;
public function __construct(Orders $orders)
{
$this->orders = $orders;
}
public function indexAction(Product $product)
{
$orders = $this->orders->findProductOrders($product);
// ...
}
}
If you don't register controllers as services:
class DefaultController extends Controller
{
public function indexAction(Product $product)
{
$orders = $this->get('repository.orders')->findProductOrders($product);
// ...
}
}
A huge advantage of this approach is that you can always change the implementation details later on. Mysql is not good enough for search anymore? Let's use elastic search, it's only a single repository!
If you need to call $product->getOrders() and fetch orders from the API behind the scenes it should still be possible with some help of doctrine's lazy loading and event listeners.