如何将Doctrine ORM默认跟踪策略更改为Deferred Explicit

Question

I am using Doctrine ORM with symfony for my latest project. I need my doctrine to use Deferred Explicit tracking policy by default - I need to control what and when to save.

I can change doctrine tracking policy for each entity in its annotations

/**
* @ORM\ChangeTrackingPolicy("DEFERRED_EXPLICIT")
*/

but I would like to make this tracking policy default for all entities. I don't want to create a common parent entity just because of this. Is there any way to set this tracking policy default for a whole project?

About doctrine tracking policies .

Tanks for your time

Answer 1

There is a Doctrine\\ORM\\Events::loadClassMetadata event, that you can hook into and create a listener that overwrites the policy in entity metadata.

The listener is called after metadata are loaded from annotations/yml/xml, before they're saved in cache, so it should be very effective.

• Events: Lifecycle Events
• Events: Load ClassMetadata Event
• Symfony: How to Register Event Listeners and Subscribers

Here's some working code:

class DoctrineTrackingPolicySubscriber implements EventSubscriber
{
    public function getSubscribedEvents()
    {
        return [
            Events::loadClassMetadata
        ];
    }

    public function loadClassMetadata(LoadClassMetadataEventArgs $args)
    {
        $classMetadata = $args->getClassMetadata();
        $classMetadata->setChangeTrackingPolicy(
            ClassMetadataInfo::CHANGETRACKING_DEFERRED_EXPLICIT
        );
    }
}

Then in services.yaml or services.yml :

App\EventSubscriber\DoctrineTrackingPolicySubscriber:
    tags:
        - { name: doctrine.event_subscriber, connection: default }

For Symfony versions < 3.3 specifying a class will be necessary, newer versions implicitly assume service name is FQCN.

Answer 2

My current solution is just a little more annoying than changing tracking policy project-wide - I have to always pass all my changed entities to EntityManager->flush($entity=null) . In other words - I have to prevent calling flush method without parameters.

Answer 3

You can change the default change tracking policy from Deferred Implicit to Deferred Explicit by defining your own factory for constructing \\Doctrine\\ORM\\Mapping\\ClassMetadata .

This method still allows your for your configuration to specify either, and otherwise only impacts where you configuration does not specify otherwise.

<?php

class MyClassMetadataFactory extends Doctrine\ORM\Mapping\ClassMetadataFactory
{
    /**
     * {@inheritDoc}
     */
    protected function newClassMetadataInstance($className)
    {
        $classMetadata = parent::newClassMetadataInstance($className);

        // Change the default Change Tracking Policy to Deferred Explicit.
        $classMetadata->setChangeTrackingPolicy(
            Doctrine\ORM\Mapping\ClassMetadataInfo::CHANGETRACKING_DEFERRED_EXPLICIT
        );

        return $classMetadata;
    }
}

$xmlMetadataConfig = \Doctrine\ORM\Tools\Setup::createXMLMetadataConfiguration([__DIR__ . '/config']);

// Set your class to be the factory for ClassMetadata.
$xmlMetadataConfig->setClassMetadataFactoryName(MyClassMetadataFactory::class);

$em = Doctrine\ORM\EntityManager::create(
    ['pdo' => $pdo],
    $xmlMetadataConfig
);

The key elements of this strategy are the following.

• Override \\Doctrine\\ORM\\Mapping\\ClassMetadataFactory::newClassMetadataInstance() to change the properties of the constructed instance of \\Doctrine\\ORM\\Mapping\\ClassMetadata .
• Set your class as the factory to be used in the configuration of the Metadata Driver.