How to Work with multiple Entity Managers and Connections

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How to Work with multiple Entity Managers and Connections

You can use multiple Doctrine entity managers or connections in a Symfony application. This is necessary if you are using different databases or even vendors with entirely different sets of entities. In other words, one entity manager that connects to one database will handle some entities while another entity manager that connects to another database might handle the rest.

Note

Using multiple entity managers is pretty easy, but more advanced and not usually required. Be sure you actually need multiple entity managers before adding in this layer of complexity.

Caution

Entities cannot define associations across different entity managers. If you need that, there are several alternatives that require some custom setup.

The following configuration code shows how you can configure two entity managers:

  • YAML
  • XML
  • PHP 
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# config/packages/doctrine.yaml
doctrine:
    dbal:
        default_connection: default
        connections:
            default:
                # configure these for your database server
                url: '%env(DATABASE_URL)%'
                driver: 'pdo_mysql'
                server_version: '5.7'
                charset: utf8mb4
            customer:
                # configure these for your database server
                url: '%env(DATABASE_CUSTOMER_URL)%'
                driver: 'pdo_mysql'
                server_version: '5.7'
                charset: utf8mb4

    orm:
        default_entity_manager: default
        entity_managers:
            default:
                connection: default
                mappings:
                    Main:
                        is_bundle: false
                        type: annotation
                        dir: '%kernel.project_dir%/src/Entity/Main'
                        prefix: 'App\Entity\Main'
                        alias: Main
            customer:
                connection: customer
                mappings:
                    Customer:
                        is_bundle: false
                        type: annotation
                        dir: '%kernel.project_dir%/src/Entity/Customer'
                        prefix: 'App\Entity\Customer'
                        alias: Customer

In this case, you've defined two entity managers and called them default and customer. The default entity manager manages entities in the src/Entity/Main directory, while the customer entity manager manages entities in src/Entity/Customer. You've also defined two connections, one for each entity manager.

Note

When working with multiple connections and entity managers, you should be explicit about which configuration you want. If you do omit the name of the connection or entity manager, the default (i.e. default) is used.

When working with multiple connections to create your databases:

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# Play only with "default" connection
$ php bin/console doctrine:database:create

# Play only with "customer" connection
$ php bin/console doctrine:database:create --connection=customer

When working with multiple entity managers to generate migrations:

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# Play only with "default" mappings
$ php bin/console doctrine:migrations:diff
$ php bin/console doctrine:migrations:migrate

# Play only with "customer" mappings
$ php bin/console doctrine:migrations:diff --em=customer
$ php bin/console doctrine:migrations:migrate --em=customer

If you do omit the entity manager's name when asking for it, the default entity manager (i.e. default) is returned:

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// ...

use Doctrine\ORM\EntityManagerInterface;

class UserController extends Controller
{
    public function index(EntityManagerInterface $entityManager)
    {
        // These methods also return the default entity manager, but it's preferred
        // to get it by injecting EntityManagerInterface in the action method
        $entityManager = $this->getDoctrine()->getManager();
        $entityManager = $this->getDoctrine()->getManager('default');
        $entityManager = $this->get('doctrine.orm.default_entity_manager');

        // Both of these return the "customer" entity manager
        $customerEntityManager = $this->getDoctrine()->getManager('customer');
        $customerEntityManager = $this->get('doctrine.orm.customer_entity_manager');
    }
}

You can now use Doctrine just as you did before - using the default entity manager to persist and fetch entities that it manages and the customer entity manager to persist and fetch its entities.

The same applies to repository calls:

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use AcmeStoreBundle\Entity\Customer;
use AcmeStoreBundle\Entity\Product;
// ...

class UserController extends Controller
{
    public function index()
    {
        // Retrieves a repository managed by the "default" em
        $products = $this->getDoctrine()
            ->getRepository(Product::class)
            ->findAll()
        ;

        // Explicit way to deal with the "default" em
        $products = $this->getDoctrine()
            ->getRepository(Product::class, 'default')
            ->findAll()
        ;

        // Retrieves a repository managed by the "customer" em
        $customers = $this->getDoctrine()
            ->getRepository(Customer::class, 'customer')
            ->findAll()
        ;
    }
}
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.