Complex References

Sometimes you may want to access references on the inverse side of a relationship where you maintain the actual MongoDbRef to one or many other documents.

You can create an immutable reference to one or many documents and specify how that reference is to be loaded. The available methods for obtaining a cursor to retrieve the references are:

• criteria - The criteria used to get a cursor.
• repositoryMethod - The repository method used to get a cursor.
• sort - What to sort the cursor by.
• skip - The number of documents to skip in the cursor.
• limit - The number of documents to limit the cursor to.

Here is an example. You could setup a reference to the last 5 comments for blog posts:

<?php

/** @Document */
class BlogPost
{
    // ...

    /** @ReferenceMany(targetDocument="Comment", mappedBy="blogPost") */
    private $comments;

    /**
     * @ReferenceMany(
     *      targetDocument="Comment",
     *      mappedBy="blogPost",
     *      sort={"date"="desc"},
     *      limit=5
     * )
     */
    private $last5Comments;
}

/** @Document */
class Comment
{
    // ...

    /** @ReferenceOne(targetDocument="BlogPost", inversedBy="comments") */
    private $blogPost;
}

You can specify a mappedBy reference for one or many so if you wanted to you could have even a $lastComment reference on the BlogPost:

<?php

/**
 * @ReferenceOne(
 *      targetDocument="Comment",
 *      mappedBy="blogPost",
 *      sort={"date"="desc"}
 * )
 */
private $lastComment;

Use an array of criteria to limit a references documents. Here we have a reference in $commentsByAdmin to the comments that are by administrators:

<?php

/**
 * @ReferenceOne(
 *      targetDocument="Comment",
 *      mappedBy="blogPost",
 *      criteria={"isByAdmin" : true}
 * )
 */
private $commentsByAdmin;

Or you can use the repositoryMethod to specify a custom method to call on the mapped repository class to get the reference:

<?php

/**
 * @ReferenceMany(
 *      targetDocument="Comment",
 *      mappedBy="blogPost",
 *      repositoryMethod="findSomeComments"
 * )
 */
private $someComments;

Now on the Comment class you would need to have a custom repository class configured:

<?php

/** @Document(repositoryClass="CommentRepository") */
class Comment
{
    // ...
}

And in the CommentRepository we can define the findSomeComments() method:

<?php

class CommentRepository extends \Doctrine\ODM\MongoDB\DocumentRepository
{
    public function findSomeComments()
    {
        return $this->findBy(array(/** ... */));
    }
}