Managing Transactions

The Domain Model isn't the place to manage transactions. The operations applied over the Domain Model should be agnostic to the persistence mechanism. A common approach to solving this problem is placing a Facade in the Application layer, thereby grouping related use cases together. When a method of the Facade is invoked from the UI layer, the business method begins a transaction. Once complete, the Facade ends the interaction by committing the transaction. If anything goes wrong, the transaction is rolled back:

use Doctrine\ORM\EntityManager;

class SomeApplicationServiceFacade
{
    private $em;

    public function __construct(EntityManager $em)
    {
        $this->em = $em;
    }

    public function doSomeUseCaseTask()
    {
        try {
            $this->em->getConnection()->beginTransaction();
            // Use domain model

            $this->em->getConnection()->commit...