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Blending the ORM and MongoDB ODM
Since the start of the Doctrine MongoDB Object Document Mapper project people have asked how it can be integrated with the ORM. This article will demonstrates how you can integrate the two transparently, maintaining a clean domain model.
This example will have a Product
that is stored in MongoDB and the Order
stored in a MySQL database.
Define Product
First lets define our Product
document:
1 <?php
namespace Documents;
/** @Document */
class Product
{
/** @Id */
private $id;
/** @String */
private $title;
public function getId()
{
return $this->id;
}
public function getTitle()
{
return $this->title;
}
public function setTitle($title)
{
$this->title = $title;
}
}
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Define Entity
Next create the Order
entity that has a $product
and $productId
property linking it to the Product
that is stored with MongoDB:
1 <?php
namespace Entities;
use Documents\Product;
/**
* @Entity
* @Table(name="orders")
*/
class Order
{
/**
* @Id @Column(type="integer")
* @GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* @Column(type="string")
*/
private $productId;
/**
* @var Documents\Product
*/
private $product;
public function getId()
{
return $this->id;
}
public function getProductId()
{
return $this->productId;
}
public function setProduct(Product $product)
{
$this->productId = $product->getId();
$this->product = $product;
}
public function getProduct()
{
return $this->product;
}
}
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Event Subscriber
Now we need to setup an event subscriber that will set the $product
property of all Order
instances to a reference to the document product so it can be lazily loaded when it is accessed the first time. So first register a new event subscriber:
So now we need to define a class named MyEventSubscriber
and pass a dependency to the DocumentManager
. It will have a postLoad()
method that sets the product document reference:
1 <?php
use Doctrine\ODM\MongoDB\DocumentManager;
use Doctrine\ORM\Event\LifecycleEventArgs;
class MyEventSubscriber
{
public function __construct(DocumentManager $dm)
{
$this->dm = $dm;
}
public function postLoad(LifecycleEventArgs $eventArgs)
{
$order = $eventArgs->getEntity();
$em = $eventArgs->getEntityManager();
$productReflProp = $em->getClassMetadata('Entities\Order')
->reflClass->getProperty('product');
$productReflProp->setAccessible(true);
$productReflProp->setValue(
$order, $this->dm->getReference('Documents\Product', $order->getProductId())
);
}
}
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The postLoad
method will be invoked after an ORM entity is loaded from the database. This allows us to use the DocumentManager
to set the $product
property with a reference to the Product
document with the product id we previously stored.
Working with Products and Orders
First create a new Product
:
Now create a new Order
and link it to a Product
in MySQL:
Later we can retrieve the entity and lazily load the reference to the document in MongoDB:
If you were to print the $order
you would see that we got back regular PHP objects:
The above would output the following:
1 Order Object
(
[id:Entities\Order:private] => 53
[productId:Entities\Order:private] => 4c74a1868ead0ed7a9000000
[product:Entities\Order:private] => Proxies\DocumentsProductProxy Object
(
[__isInitialized__] => 1
[id:Documents\Product:private] => 4c74a1868ead0ed7a9000000
[title:Documents\Product:private] => Test Product
)
)
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