Symfony and Doctrine: cross database relations

I have two entities Entity1 and Entity2 with a OneToMany relation, but they live in two MySQL databases.

How can I implement those entities with their relation in Symfony?

Is it possible to create two separated bundles where to implement those entities?

In Doctrine, joining data across databases is not technically “supported” by a designed feature, but you can make it work by tricking Doctrine a little bit.

If you want to build a relationship between entities then they must use the same connection: same database.

The key to getting multiple databases to work is within your entity classes, you need to specify the table name of the entity with a prefix of the name of the database to which the table belongs. Here is an example using annotations:

<?php
namespace Demo\UserBundle\Entity;

use DoctrineORMMapping as ORM;

/**
 * Demo\UserBundle\Entity\User
 *
 * @ORMTable(name="users.User")
 */
class User implements
{
  /* ... */
}

and

<?php
namespace Demo\PostBundle\Entity;

use DoctrineORMMapping as ORM;

/**
 * Demo\PostBundle\Entity\Post
 *
 * @ORMTable(name="posts.Post")
 */
class Post implements
{
  /* ... */
}

and the relation table:

<?php
namespace Demo\PostBundle\Entity;

use DoctrineORMMapping as ORM;

/**
 * Demo\PostBundle\Entity\Post
 *
 * @ORMTable(name="posts.Post")
 */
class Post implements
{
    /**
     * @ORM\ManyToOne(targetEntity="\Demo\UserBundle\Entity\User")
     **/
    private $user;

    /* ... */

    /**
     * Set user
     *
     * @param \Demo\UserBundle\Entity\Site $site
     * @return Post
     */
    public function setUser($user)
    {
        $this->user = $user;

        return $this;
    }

    /**
     * Get user
     *
     * @return \Demo\UserBundle\Entity\Site
     */
    public function getUser()
    {
        return $this->user;
    }
}

Here an article about it.

Hope this help