Multiple level of different kind of inheritance - php

Question

For my project, I'm trying to use the inheritance feature of Doctrine. I need to represent medias (through different tables : one table for uploaded documents, one for linked videos, ... and so on).
But, the videos can vary from provider to provider (such as Youtube, Dailymotion, you name it). So, I was thinking of doing another inheritance, proper to the Video table, through a SINGLE_TABLE inheritance.
But, when I declare my entities, it seems that if I add the SINGLE_TABLE inheritance annotation on the AbstractVideo entity, which extends the AbstractMedia Entity, the Video table is never created (nor detected). Here is a snippet of these two entities :
<?php
namespace Acme\Demo\Entity;
use Datetime;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity
* #ORM\Table(name="Media")
* #ORM\InheritanceType("JOINED")
* #ORM\DiscriminatorColumn(name="type", type="string")
*/
abstract class AbstractMedia
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
// some other fields
}
/**
* #ORM\Entity
* #ORM\Table(name="Video")
* #ORM\InheritanceType("SINGLE_TABLE")
* #ORM\DiscriminatorColumn(name="provider", type="string")
* #ORM\DiscriminatorMap({})
*/
abstract class AbstractVideo extends AbstractMedia
{
/** #ORM\Column(type="string") */
private $name;
// some other fields
}
I already tried to have a mapped entity to a Foo entity, extending the AbstractVideo, but then when I try to persist something, it says that it is not a valid entity.
Any ideas, or should I really avoid such deep inheritance ? Thanks

Answer 1

Not really sure if this is exactly what you need, but this is from a production code I use.
We inherit the file, with other entities, and those are also inherited.
The important part is to add the inheriting(extending) entities to disciminator map.
/**
* File
*
* #ORM\Table(name = "file")
* #ORM\Entity(repositoryClass="Living\ApiBundle\Entity\File\FileRepository")
* #ORM\InheritanceType("JOINED")
* #ORM\DiscriminatorColumn(name="type", type="string", length=64)
* #ORM\DiscriminatorMap({
* "file" = "Something\Entity\File\File",
* "image" = "Something\Entity\Image\Image",
* "specialImage" = "Something\Entity\Image\SpecialImage",
* })
*/
class File implements FileEntityInterface
.....
/**
* ImageFile
*
* #ORM\Table(name="image")
* #ORM\Entity(repositoryClass="Living\ApiBundle\Entity\Image\ImageRepository")
*/
class Image extends File implements ImageEntityInterface

Answer 2

As #OCramius said in a comment to my question, this is not supported by Doctrine ORM. So to do what I wanted to do, I will store a value object in the data property of my object, storing the property of "child classes" instead of having deep different kind of inheritance.
<?php
class Video extends AbstractMedia
{
// returns the value object youtube, dailymotion, ... etc
public function getData();
}
class Youtube
{
//public function ...
}
class Dailymotion
{
// public funciton ...
}