Prevent document suppression when they are embedded

Context

In a document oriented database (like Mongo), to improve performances, a standard practice is to avoid relations between documents using embed documents. However, when you want to suppress a document that is used by other documents a little issue can appear.

In our case, the Open Orchestra Backoffice presents some status that can be used in multiple documents like the Node, Content, Role, ... . Deleting a Status document could lead to a loss of consistence from the database.

Open Orchestra implementation example

In Open Orchestra, if you look to the DeleteStatusVoter you will see it using the StatusUsageFinder to check if the Status can be deleted.

If you add a document implementing StatusableInterface :

• Your document repository should implement StatusableElementRepositoryInterface
• You should add your repository to the StatusUsageFinder service

Implement the interface

In the NodeRepository class, the interface implements the StatusableElementRepositoryInterface :

interface NodeRepositoryInterface extends StatusableElementRepositoryInterface

And the repository implement the method :

public function hasStatusedElement(StatusInterface $status)
{
    $node = $this->findOneBy(array('status' => $status));
    return $node instanceof NodeInterface;
}

Modify the configuration

To add your repository, foo.repository.bar in our example, you should modify the usage finder definition in your bundle :

class FooBarExtension extends Extension
{
    public function load(array $configs, ContainerBuilder $container)
    {
        $definition = $container->getDefinition('open_orchestra_backoffice.usage_finder.status')
        $definition->addMethodCall('addRepository', array(new Reference('foo.repository.bar')));
    }
}

With this modification, each time the StatusUsageFinder is called, it will also check in your own repository if the given status is used.