Link 1 entity with many others kind of entities - symfony

Question

Let say I have a Company for which I manage Employees, Cars, Contracts, Buildings, Sites, Products, etc. As you can guess, these are quite independant things, so no inheritance is possible.
For each of these elements (i.e. Entities), I want to be able to attach one or several Documents (click on a button, form opens, select one/several Document or upload a new one).
Linking Document to one kind of entity is not a problem, my problem is that there are many kinds of entities. How should I manage that? I have 2 ideas which have their own problems...:
Create a ManyToMany relationship between Document and Employee, another between Document and Car, etc.
Problem: I have to duplicate the Controller code to attach Document, duplicate the forms, etc.
Create a single join table containing the Document's ID, the related entity's ID and the related entity's class name.
Problem: it doesn't look really clean to me, I didn't really dig in this way but I feel I'll have a lot of "entity mapping" problems.
Any suggestion?
[EDIT]
In fact I have to do the same for Event as well: I need to link some Events to some Employees and/or to some Cars, etc. And in my real case, I have more than 10 Entities to be linked to Event and/or Document, which means duplicating more tha 20 times the code if I go with the solution 1!

Answer 1

Assuming you're using Doctrine ORM, i think you're searching for the Mapped Superclasses inheritance.
The docs are better than words :
http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/inheritance-mapping.html#mapped-superclasses

Answer 2

So finally I managed to solve my problem, following #Rpg600 idea about Mapped Superclasses.
This is probably not the best and cleanest solution ever, I'm not really proud of it but it does the job and it is still better than my first ideas.
I create a BaseEntity which is my a mapped superclass (Employee, Car, etc. Entities have to extend this Class):
/**
* BaseEntity
* #ORM\MappedSuperclass
*/
class BaseEntity {
/**
* #ORM\OneToOne(targetEntity="MyProject\MediaBundle\Entity\Folder")
*/
private $folder;
/**
* Set folder
* #param \Webobs\MediaBundle\Entity\Folder $folder
* #return BaseEntity
*/
public function setFolder(\Webobs\MediaBundle\Entity\Folder $folder = null){
$this->folder = $folder;
return $this;
}
/**
* Get folder
* #return \Webobs\MediaBundle\Entity\Folder
*/
public function getFolder(){
return $this->folder;
}
}
As it is not possible to have a Many-to-Many relationship in a superclass, I use a Folder which will contain one or several Document. This is the dirty part of the solution ; the folder table basically contain only one field which is the id...
class Folder
{
private $id;
/**
* Note : Proprietary side
* #ORM\ManyToMany(targetEntity="MyProject\MediaBundle\Entity\Document", inversedBy="folders", cascade={"persist"})
* #ORM\JoinTable(name="document_in_folder")
*/
private $documents;
// setters and getters
Then I create a helper class (which is declared as a service) to manage the link between any Entity and the Document:
class DocumentHelper extends Controller
{
protected $container;
/** ************************************************************************
* Constructor
* #param type $container
**************************************************************************/
public function __construct($container = null)
{
$this->container = $container;
}
/** ************************************************************************
* Attach Document(s) to an $entity according to the information given in the
* form.
* #param Entity $entity
* #param string $redirectRouteName Name of the route for the redirection after successfull atachment
* #param string $redirectParameters Parameters for the redirect route
* #return Response
**************************************************************************/
public function attachToEntity($entity, $redirectRouteName, $redirectParameters)
{
$folder = $entity->getFolder();
if($folder == NULL){
$folder = new Folder();
$entity->setFolder($folder);
}
$form = $this->createForm(new FolderType(), $folder);
// ------------- Request Management ------------------------------------
$request = $this->get('request');
if ($request->getMethod() == 'POST') {
$form->bind($request); // Link Request and Form
if ($form->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->persist($folder);
$em->persist($entity);
$em->flush();
return $this->redirect($this->generateUrl($redirectRouteName, $redirectParameters));
}
}
return $this->render('MyProjectMediaBundle:Folder:addDocument.html.twig', array(
'form' => $form->createView(),
'entity' => $entity,
));
}
Doing that way, I just have to add one small action in each relevant controller, let say EmployeeController.php:
public function addDocumentAction(Employee $employee)
{
$redirectRouteName = 'MyProjectCore_Employee_see';
$redirectParameters = array('employee_id' => $employee->getId());
return $this->get('myprojectmedia.documenthelper')->attachToEntity($employee,$redirectRouteName,$redirectParameters);
}
Same principle for the display, in the helper I have the common function which I call in my already-existing seeAction() and in the TWIG file I import the common "Document list" display.
That's all folks!
I hope this can help :)