Doctrine Key Value Stores

This is a work in progress design document for this component

The Persistence interfaces are rather overkill for many implementations in the NoSQL world that are only key-value stores with some additional features on top. Doctrine Key Value Store for the rescue. This project offers a much simpler lightweight API that is centered on a key-value API to fetch/save objects.

• Single- or multi-value primary keys
• Unstructured/schema-less values that are mapped onto objects
• Depending on the implementation embedded values/objects are supported
• No complex mapping necessary, just put @Entity on the class and all properties are automatically mapped unless @Transient is given. At least one property has to be @Id. Depends on the underlying vendor though.
• Properties dont have to exist on the class, public properties are created for missing ones.
• No support for references to other objects
• EventListener for ODM/ORM that allows to manage key-value entities and collections of them as properties (postLoad, postUpdate, postPersist, postRemove)
• Stripped down Object Manager Interface
• Data-mapper as any other Doctrine library and persistence and data-objects are seperated.
• Inheritance (Single- or Multiple-Storage)

Implementations

Following vendors are targeted:

• Microsoft Azure Table (Implemented)
• Doctrine\Common\Cache provider (Implemented)
• RDBMS (Implemented)
• Couchbase
• Amazon DynamoDB
• CouchDB
• MongoDB
• Riak (Implemented)

We happily accept contributions for any of the drivers.

Example

Suppose we track e-mail campaigns based on campaign id and recipients.

use Doctrine\KeyValueStore\Mapping\Annotations as KeyValue;

/**
 * @KeyValue\Entity(storageName="responses")
 */
class Response
{
    const RECIEVE = 0;
    const OPEN = 10;
    const CLICK = 20;
    const ACTION = 30;

    /** @KeyValue\Id */
    private $campaign;
    /** @KeyValue\Id */
    private $recipient;
    private $status;
    private $date;

    public function __construct($campaign, $recipient, $status)
    {
        $this->campaign = $campaign;
        $this->recipient = $recipient;
        $this->status = $status;
    }
}

$response = new Response("1234", "[email protected]", Response::RECIEVE);

$entityManager->persist($response);
//.... persists as much as you can :-)

$entityManager->flush();

Configuration

There is no factory yet that simplifies the creation process, here is the full code necessary to instantiate a KeyValue EntityManager with a Doctrine Cache backend:

use Doctrine\KeyValueStore\EntityManager;
use Doctrine\KeyValueStore\Mapping\AnnotationDriver;
use Doctrine\KeyValueStore\Storage\DoctrineCacheStorage;
use Doctrine\Common\Cache\ArrayCache;
use Doctrine\Common\Annotations\AnnotationReader;

$storage = new DoctrineCacheStorage($cache);
$cache = new ArrayCache;
$metadata = new AnnotationDriver(new AnnotationReader);
$entityManager = new EntityManager($storage, $cache, $metadata);

If you want to use WindowsAzure Table you can use the following configuration to instantiate the storage:

use Doctrine\KeyValueStore\Storage\WindowsAzureTableStorage;
use Doctrine\KeyValueStore\Storage\WindowsAzureTable\SharedKeyLiteAuthorization;
use Doctrine\KeyValueStore\Http\SocketClient;

$name = ""; // Windows Azure Storage Account Name
$key = ""; // Windows Azure Storage Account Key

$auth = new SharedKeyLiteAuthorization($name, $key);
$storage = new WindowsAzureTableStorage(new SocketClient(), $name, $auth);

If you want to use Doctrine DBAL as backend:

$params = array();
$tableName = "storage";
$idColumnName = "id";
$dataColumnName = "serialized_data";

$conn = DriverManager::getConnection($params);
$storage = new DBALStorage($conn, $tableName, $idColumnName, $dataColumnName);