Doctrine MongoDB Object Document Mapper

A question asked to me many times by many different people over the last year is, “will Doctrine ever have any support for MongoDB?”. I have never really had an answer because we haven’t had any official plans to support it as it was so new to the database world and php so nobody really knew much about it yet.

A few weekends ago I decided to install MongoDB and give it a try. It was pretty fun and interesting. I quickly learned that it being a document based storage system lends itself well to a object mapper so the experimental Doctrine MongoDB Object Document Mapper was born.

Introducing Doctrine MongoDB Object Document Mapper (ODM)

Much like the Doctrine 2 ORM, the ODM aims to provide transparent persistence for PHP 5.3.0+ objects. You will notice that the Doctrine 2 ORM and ODM infrastructure, style, interfaces, etc. are all very similar. Instead of an EntityManager like in the ORM you have the DocumentManager. Map your objects in the same way you do for the ORM. Here is an examle User document:

<?php
/** @Document(db="my_db", collection="users") */
class User
{
    /** @Id */
    private $id;

    /** @String */
    private $username;

    /** @String */
    private $password;

    // ...
}

Now like you would expect you can create new instances and persist them to Mongo:

<?php
$user = new User();
$user->setUsername('jwage');
$user->setPassword('testing');

$dm->persist($user);
$dm->flush();

Now if you have a look in MongoDB you will see a database named my_db and a collection named users containing a new document like the following:

array(
  '_id' => instanceof MongoId,
  'username' => 'jwage',
  'password' => 'testing'
)

When you query for and retrieve this document from the database later, Doctrine reconstructs the PHP object with the data from MongoDB:

<?php
$user = $dm->findOne('User', array('username' => 'jwage')); // instanceof User
echo $user->getUsername();

Below you can find an overview list of the features available:

  • Transparent persistence.
  • Map one or many embedded documents.
  • Map one or many referenced documents.
  • Create references between documents in different databases.
  • Map documents with Annotations, XML, YAML or plain old PHP code.
  • Documents can be stored on the MongoGridFS.
  • Collection per class(concrete) and single collection inheritance supported.
  • Map your Doctrine 2 ORM Entities to the ODM and use mixed data stores.
  • Inserts are performed using MongoCollection::batchInsert()
  • Updates are performed using $set instead of saving the entire document.

Getting Started?

We’ve put together a little documentation to help you get familiar with the ODM quickly.

How can I contribute?

Get your fork on! All you need to do is fork a Doctrine repository on github.com and submit your modifications to us by sending a pull request.

You can also take part in discussions on our mailing list or join #doctrine on irc.freenode.net for live support from the community.

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