Doctrine ODM Get By Id with mixed type

Question

I have a collection of mixed type like defined here: http://www.doctrine-project.org/2010/07/20/mixing-types-of-documents.html

/**
 * @Document(collection="my_documents")
 * @DiscriminatorField(fieldName="type")
 * @DiscriminatorMap({"article"="Article", "album"="Album"})
 */
class Article
{
    // ...
}

Album

/**
 * @Document(collection="my_documents")
 * @DiscriminatorField(fieldName="type")
 * @DiscriminatorMap({"article"="Article", "album"="Album"})
 */
class Album
{
    // ...
}

I would like to retrieve any object of that collection with a given Id.

Something like

$object = $dm->find(['Article','Album'], $id);

I can't use that because find take a Document Name. It would be :

$article = $dm->find('Article', $id);
$album = $dm->find('Album', $id);

I have tried to create my own query but it always return null.

$qb = $dm->createQueryBuilder(['Article', 'Album']);
$qb
   ->elemMatch(['id' => $id])
;
$result  = $qb->getQuery()->execute();

Do you have any idea?

Answer 1

The easiest solution is to introduce a parent class from which both Article and Album extend. Thanks to that you'll also be able to specify @DiscriminatorMap once:

/**
 * @Document(collection="my_documents")
 * @DiscriminatorField(fieldName="type")
 * @DiscriminatorMap({"article"="Article", "album"="Album"})
 * @InheritanceType("SINGLE_COLLECTION")
 */
abstract class Item {  }

/**
 * @Document()
 */
class Album extends Item { /* ... */ }

/**
 * @Document()
 */
class Article extends Item { /* ... */ }

Now whenever you would want to look for documents of both types at a same time you can use:

$item = $dm->find(Item::class, $id);

Depending on what is stored in the database, $item will come back either as an Article or an Album. Furthermore you can do the same with repository:

$items = $dm->getRepository(Item::class)->findAll();