chamilo-lms2/vendor/gedmo/doctrine-extensions/doc/reference_integrity.md

Reference Integrity behavior extension for Doctrine 2

ReferenceIntegrity behavior will automate the reference integrity for referenced documents. It works through annotations and yaml, and supports 'nullify' and 'restrict' which throws an exception.

So let's say you have a Type which is referenced to multiple Articles, when deleting the Type, by default the Article would still have a reference to Type, since Mongo doesn't care. When setting the ReferenceIntegrity to 'nullify' it would then automatically remove the reference from Article.

Features:

• Automatically remove referenced association
• ODM only
• ReferenceOne and ReferenceMany support
• 'nullify' and 'restrict' support
• Annotation and Yaml mapping support for extensions

Symfony:

• ReferenceIntegrity is available as Bundle for Symfony2, together with all other extensions

This article will cover the basic installation and functionality of ReferenceIntegrity behavior

Content:

• Including the extension
• Document example
• Yaml mapping example
• Usage examples

Setup and autoloading

Read the documentation or check the example code on how to setup and use the extensions in most optimized way.

ReferenceIntegrity Document example:

<?php
namespace Document;

use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;
use Gedmo\Mapping\Annotation as Gedmo;

/**
 * @ODM\Document(collection="types")
 */
class Type
{
    /**
     * @ODM\Id
     */
    private $id;

    /**
     * @ODM\String
     */
    private $title;

    /**
     * @ODM\ReferenceOne(targetDocument="Article", mappedBy="type")
     * @Gedmo\ReferenceIntegrity("nullify")
     * @var Article
     */
    protected $article;

    // ...
}

It is necessary to have the 'mappedBy' option set, to be able to access the referenced documents. On removal of Type, on the referenced Article the Type reference will be nullified (removed)

Yaml mapping example:

Yaml mapped Article: /mapping/yaml/Documents.Article.dcm.yml

---
Document\Type:
  type: document
  collection: types
  fields:
      id:
          id:     true
      title:
          type:   string
      article:
          reference: true
          type: one
          mappedBy: type
          targetDocument: Document\Article
          gedmo:
              referenceIntegrity: nullify   # or restrict

It is necessary to have the 'mappedBy' option set, to be able to access the referenced documents.

Usage examples:

Few operations to see it in action:

<?php
$article = new Article;
$article->setTitle('My Article');

$type = new Type;
$type->setTitle('Published');

$article = $em->getRepository('Entity\Article')->findByTitle('My Article');
$article->setType($type);

$em->persist($article);
$em->persist($type);
$em->flush();

$type = $em->getRepository('Entity\Type')->findByTitle('Published');
$em->remove($type);
$em->flush();

$article = $em->getRepository('Entity\Article')->findByTitle('My Article');
$article->getType(); // won't be referenced to Type anymore

When 'ReferenceIntegrity' is set to 'restrict' a ReferenceIntegrityStrictException will be thrown, only when there is a referenced document.

Easy like that, any suggestions on improvements are very welcome