Doctrine 2 - not able to save one to many self-reference relationship - doctrine

I have a problem saving a one to many self-reference relationship, both parent and children are saved properly on the database, but Im getting parent_id null for the children.
I folloed the doctrine example ... but no idea
namespace CD\Entity;
/**
* #Entity
*/
class Category {
/**
* #Id
* #Column(type="integer")
* #GeneratedValue(strategy="IDENTITY")
*/
private $id;
/** #Column(type="string",length=50) */
private $name;
/**
* #OneToMany(targetEntity="Category", mappedBy="parent",cascade={"persist"})
*/
private $children;
/**
* #ManyToOne(targetEntity="Category", inversedBy="children")
* #JoinColumn(name="parent_id", referencedColumnName="id")
*/
private $parent;
// setters and getters ...
}
and my controller here:
public function insertAction()
{
$cm = new CD\Entity\Category();
$cc = new CD\Entity\Category();
$cm->name = 'mainCat';
$cc->name = 'childCat';
$cm->children = array($cc);
$this->_em->persist($cm);
$this->_em->flush();
}
I really dont know what im doing wrong

Have you tried out Doctrine Extensions, particularly the tree extension? It makes work like this extremely easy.

You need to persist ALL of your entities.
And after running (assuming you use doctrine)
doctrine:generate:entities CD/Entity
Your will have a function named "Category->addChildren" which should be used to add children to an existing category entity.
Try this:
public function insertAction()
{
$cm = new CD\Entity\Category();
$cc = new CD\Entity\Category();
$cm->setName('mainCat');
$cc->setName('childCat');
$cm->addChildren($cc);
$this->_em->persist($cm);
$this->_em->persist($cc);
$this->_em->flush();
}

Related

Symfony 2.8 - Oracle : ManyToMany return The column id must be mapped to a field in class

I have Two entity has ManyToMany relation between them blogPost et Category et the associative table blogPost_Category.
PS: The tables exist in the database.
So, I starting to create the entities
<?php
use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\Mapping\Id;
use Doctrine\ORM\Mapping\Column;
/**
*#ORM\Table(name="blogPost")
*#ORM\Entity("App\TestBundle\Repository\BlogPostRepository")
*/
class blogPost {
/**
*#Id
*Column(name="ID", type="integer", length=20, nullable=false, unique=true)
*/
private $id;
.
.
.
/**
*#ORM\ManyToMany(targetEntity="Category", inversedBy="blogPosts")
*#ORM\JoinTable(name="blogPost_Category",
*joinColumns={#ORM\JoinColumn(name="id", referencedColumnName="id")},
*inverseJoinColumns={#ORM\joinColumn(name="id", referencedColumnName="id")}
*)
*/
private $categories;
public function __construct()
{
$this->categories = new ArrayCollection();
}
public function getCategories()
{
return $this->categories;
}
.
.
.
The other Entity has the same data and structure,
And when I call for example the getCategories on the controller I get this error
The column id must be mapped to a field in class
App\TestBundle\Entity\blogPost since it is referenced by a join column
of another class.
is there any solution?
if not, Can I create entity for the associative table and use ManyToOne on the two directions?
You have multiple id reference in your join table, you do not have to specify the name if you don't want to, so you could change your ORM to :
/**
* #ORM\ManyToMany(targetEntity="Category", inversedBy="blogPosts")
* #ORM\JoinTable(name="blogPost_Category")
*/ private $categories;
And in your Category entity :
/**
* #ORM\ManyToMany(targetEntity="BlogPost", mappedBy="categories")
*/
Do not forget to update your schema.

Doctrine 2: Oracle Insert Trigger

i currently started to work with the symfony2 framework and doctrine2.
I have the following problem here with using doctrine when I want to insert an object.
Following given situation:
The table uses a sequence, that generates the ID via BEFORE INSERT
Trigger
The sequence is uses by other tables as well, so there is no name
convention like: $table->getName() . '_SEQ'; (see
Doctrine/DBAL/Platforms/OraclePlatform.php getIdentitySequenceName())
The sequence that should be uses id called: general_data_seq
The design of the tables and triggers is given and cannot be changed.
I have made the following entity:
/**
* #ORM\Entity
* #ORM\Table(name="test")
*
*/
class Test
{
/**
* #ORM\Column(type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #ORM\Column(type="string")
*/
private $name;
/**
* #param int $id
*/
public function setId($id)
{
$this->id = $id;
}
/**
* #return string
*/
public function getName() : string
{
return $this->name;
}
/**
* #return string
*/
public function setName(string $name)
{
$this->name = $name;
}
}
If i want to save this using doctrine like this
$em = $this->getDoctrine()->getManager();
$test = new Test();
$test->setName('Max');
$em->persist($test);
$em->flush();
I'm getting the message:
ORA-02289: sequence does not exist.
What is true, since the sequence that should be use really does not exist.
My question now is: How to use docrine here so that the persisted entity has the inserted id generated by the trigger?
I found a related problem here:
Doctrine 2: cascade persist Oracle "IDENTITY" is returning 0 as last inserted ID
and here: https://github.com/doctrine/dbal/issues/1772
but nighter of them helped me to find a solution, since they are still bases on using the table-named-sequence.

how to sort an entity's arrayCollection in symfony2

I have an entity "container" with this property
/**
* #ORM\OneToMany(targetEntity="BizTV\ContentManagementBundle\Entity\Content", mappedBy="container")
*/
private $content;
the property is an array collection...
public function __construct() {
$this->content = new \Doctrine\Common\Collections\ArrayCollection();
}
...with these two standard methods
/**
* Add content
*
* #param BizTV\ContentManagementBundle\Entity\Content $content
*/
public function addContent(\BizTV\ContentManagementBundle\Entity\Content $content)
{
$this->content[] = $content;
}
/**
* Get content
*
* #return Doctrine\Common\Collections\Collection
*/
public function getContent()
{
return $this->content;
}
Now my question is, is there a smooth way to build a sorting feature into this, perhaps on the getContent() call? I am no php wiz and certainly not seasoned in symfony2 but I learn as I go.
The content entity itself has a sorting INT like this that I want to sort it on:
/**
* #var integer $sortOrder
*
* #ORM\Column(name="sort_order", type="integer")
*/
private $sortOrder;
You should be able to use the #ORM\OrderBy statement which allows you to specify columns to order collections on:
/**
* #ORM\OneToMany(targetEntity="BizTV\ContentManagementBundle\Entity\Content", mappedBy="container")
* #ORM\OrderBy({"sort_order" = "ASC"})
*/
private $content;
In fact this may be a duplicate of How to OrderBy on OneToMany/ManyToOne
Edit
Checking for implementation advice it appears that you must fetch the tables with a join query to the collection in order for the #ORM\OrderBy annotation to work: http://www.krueckeberg.org/notes/d2.html
This means that you must write a method in the repository to return the container with the contents table joined.
If you want to be sure that you always get your relations in the order based on current property values, you can do something like this:
$sort = new Criteria(null, ['Order' => Criteria::ASC]);
return $this->yourCollectionProperty->matching($sort);
Use that for example if you've changed the Order property. Works great for a "Last modified date" as well.
You can write
#ORM\OrderBy({"date" = "ASC", "time" = "ASC"})
for multiple criteria ordering.
You can also sort ArrayCollection by Criteria property orderBy like so:
<?php
namespace App/Service;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Criteria;
/**
* Class SortService
*
* #package App\Service
*/
class SortService {
/**
* #param SomeAbstractObject $object
* #return SomeCollectionItem[]
*/
public function sorted(SomeAbstractObject $object): array {
/** $var ArrayCollection|SomeCollectionItem[] */
$collection = $object->getCollection();
// convert normal array to array collection object
if(\is_array(collection)) {
$collection = new ArrayCollection(collection);
}
// order collection items by position property
$orderBy = (Criteria::create())->orderBy([
'position' => Criteria::ASC,
]);
// return sorted SomeCollectionItem array
return $collection->matching($orderBy)->toArray();
}
}
?>

How to encode Doctrine entities to JSON in Symfony 2.0 AJAX application?

I'm developing game app and using Symfony 2.0. I have many AJAX requests to the backend. And more responses is converting entity to JSON. For example:
class DefaultController extends Controller
{
public function launchAction()
{
$user = $this->getDoctrine()
->getRepository('UserBundle:User')
->find($id);
// encode user to json format
$userDataAsJson = $this->encodeUserDataToJson($user);
return array(
'userDataAsJson' => $userDataAsJson
);
}
private function encodeUserDataToJson(User $user)
{
$userData = array(
'id' => $user->getId(),
'profile' => array(
'nickname' => $user->getProfile()->getNickname()
)
);
$jsonEncoder = new JsonEncoder();
return $jsonEncoder->encode($userData, $format = 'json');
}
}
And all my controllers do the same thing: get an entity and encode some of its fields to JSON. I know that I can use normalizers and encode all entitities. But what if an entity has cycled links to other entity? Or the entities graph is very big? Do you have any suggestions?
I think about some encoding schema for entities... or using NormalizableInterface to avoid cycling..,
With php5.4 now you can do :
use JsonSerializable;
/**
* #Entity(repositoryClass="App\Entity\User")
* #Table(name="user")
*/
class MyUserEntity implements JsonSerializable
{
/** #Column(length=50) */
private $name;
/** #Column(length=50) */
private $login;
public function jsonSerialize()
{
return array(
'name' => $this->name,
'login'=> $this->login,
);
}
}
And then call
json_encode(MyUserEntity);
Another option is to use the JMSSerializerBundle. In your controller you then do
$serializer = $this->container->get('serializer');
$reports = $serializer->serialize($doctrineobject, 'json');
return new Response($reports); // should be $reports as $doctrineobject is not serialized
You can configure how the serialization is done by using annotations in the entity class. See the documentation in the link above. For example, here's how you would exclude linked entities:
/**
* Iddp\RorBundle\Entity\Report
*
* #ORM\Table()
* #ORM\Entity(repositoryClass="Iddp\RorBundle\Entity\ReportRepository")
* #ExclusionPolicy("None")
*/
....
/**
* #ORM\ManyToOne(targetEntity="Client", inversedBy="reports")
* #ORM\JoinColumn(name="client_id", referencedColumnName="id")
* #Exclude
*/
protected $client;
You can automatically encode into Json, your complex entity with:
use Symfony\Component\Serializer\Serializer;
use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;
use Symfony\Component\Serializer\Encoder\JsonEncoder;
$serializer = new Serializer(array(new GetSetMethodNormalizer()), array('json' => new
JsonEncoder()));
$json = $serializer->serialize($entity, 'json');
To complete the answer: Symfony2 comes with a wrapper around json_encode:
Symfony/Component/HttpFoundation/JsonResponse
Typical usage in your Controllers:
...
use Symfony\Component\HttpFoundation\JsonResponse;
...
public function acmeAction() {
...
return new JsonResponse($array);
}
I found the solution to the problem of serializing entities was as follows:
#config/config.yml
services:
serializer.method:
class: Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer
serializer.encoder.json:
class: Symfony\Component\Serializer\Encoder\JsonEncoder
serializer:
class: Symfony\Component\Serializer\Serializer
arguments:
- [#serializer.method]
- {json: #serializer.encoder.json }
in my controller:
$serializer = $this->get('serializer');
$entity = $this->get('doctrine')
->getRepository('myBundle:Entity')
->findOneBy($params);
$collection = $this->get('doctrine')
->getRepository('myBundle:Entity')
->findBy($params);
$toEncode = array(
'response' => array(
'entity' => $serializer->normalize($entity),
'entities' => $serializer->normalize($collection)
),
);
return new Response(json_encode($toEncode));
other example:
$serializer = $this->get('serializer');
$collection = $this->get('doctrine')
->getRepository('myBundle:Entity')
->findBy($params);
$json = $serializer->serialize($collection, 'json');
return new Response($json);
you can even configure it to deserialize arrays in http://api.symfony.com/2.0
I just had to solve the same problem: json-encoding an entity ("User") having a One-To-Many Bidirectional Association to another Entity ("Location").
I tried several things and I think now I found the best acceptable solution. The idea was to use the same code as written by David, but somehow intercept the infinite recursion by telling the Normalizer to stop at some point.
I did not want to implement a custom normalizer, as this GetSetMethodNormalizer is a nice approach in my opinion (based on reflection etc.). So I've decided to subclass it, which is not trivial at first sight, because the method to say if to include a property (isGetMethod) is private.
But, one could override the normalize method, so I intercepted at this point, by simply unsetting the property that references "Location" - so the inifinite loop is interrupted.
In code it looks like this:
class GetSetMethodNormalizer extends \Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer {
public function normalize($object, $format = null)
{
// if the object is a User, unset location for normalization, without touching the original object
if($object instanceof \Leonex\MoveBundle\Entity\User) {
$object = clone $object;
$object->setLocations(new \Doctrine\Common\Collections\ArrayCollection());
}
return parent::normalize($object, $format);
}
}
I had the same problem and I chosed to create my own encoder, which will cope by themself with recursion.
I created classes which implements Symfony\Component\Serializer\Normalizer\NormalizerInterface, and a service which holds every NormalizerInterface.
#This is the NormalizerService
class NormalizerService
{
//normalizer are stored in private properties
private $entityOneNormalizer;
private $entityTwoNormalizer;
public function getEntityOneNormalizer()
{
//Normalizer are created only if needed
if ($this->entityOneNormalizer == null)
$this->entityOneNormalizer = new EntityOneNormalizer($this); //every normalizer keep a reference to this service
return $this->entityOneNormalizer;
}
//create a function for each normalizer
//the serializer service will also serialize the entities
//(i found it easier, but you don't really need it)
public function serialize($objects, $format)
{
$serializer = new Serializer(
array(
$this->getEntityOneNormalizer(),
$this->getEntityTwoNormalizer()
),
array($format => $encoder) );
return $serializer->serialize($response, $format);
}
An example of a Normalizer :
use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
class PlaceNormalizer implements NormalizerInterface {
private $normalizerService;
public function __construct($normalizerService)
{
$this->service = normalizerService;
}
public function normalize($object, $format = null) {
$entityTwo = $object->getEntityTwo();
$entityTwoNormalizer = $this->service->getEntityTwoNormalizer();
return array(
'param' => object->getParam(),
//repeat for every parameter
//!!!! this is where the entityOneNormalizer dealt with recursivity
'entityTwo' => $entityTwoNormalizer->normalize($entityTwo, $format.'_without_any_entity_one') //the 'format' parameter is adapted for ignoring entity one - this may be done with different ways (a specific method, etc.)
);
}
}
In a controller :
$normalizerService = $this->get('normalizer.service'); //you will have to configure services.yml
$json = $normalizerService->serialize($myobject, 'json');
return new Response($json);
The complete code is here : https://github.com/progracqteur/WikiPedale/tree/master/src/Progracqteur/WikipedaleBundle/Resources/Normalizer
in Symfony 2.3
/app/config/config.yml
framework:
# сервис конвертирования объектов в массивы, json, xml и обратно
serializer:
enabled: true
services:
object_normalizer:
class: Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer
tags:
# помечаем к чему относится этот сервис, это оч. важно, т.к. иначе работать не будет
- { name: serializer.normalizer }
and example for your controller:
/**
* Поиск сущности по ИД объекта и ИД языка
* #Route("/search/", name="orgunitSearch")
*/
public function orgunitSearchAction()
{
$array = $this->get('request')->query->all();
$entity = $this->getDoctrine()
->getRepository('IntranetOrgunitBundle:Orgunit')
->findOneBy($array);
$serializer = $this->get('serializer');
//$json = $serializer->serialize($entity, 'json');
$array = $serializer->normalize($entity);
return new JsonResponse( $array );
}
but the problems with the field type \DateTime will remain.
This is more an update (for Symfony v:2.7+ and JmsSerializer v:0.13.*#dev), so to avoid that Jms tries to load and serialise the whole object graph ( or in case of cyclic relation ..)
Model:
use Doctrine\ORM\Mapping as ORM;
use JMS\Serializer\Annotation\ExclusionPolicy;
use JMS\Serializer\Annotation\Exclude;
use JMS\Serializer\Annotation\MaxDepth; /* <=== Required */
/**
* User
*
* #ORM\Table(name="user_table")
///////////////// OTHER Doctrine proprieties //////////////
*/
public class User
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
protected $id;
/**
* #ORM\ManyToOne(targetEntity="FooBundle\Entity\Game")
* #ORM\JoinColumn(nullable=false)
* #MaxDepth(1)
*/
protected $game;
/*
Other proprieties ....and Getters ans setters
......................
......................
*/
Inside an Action:
use JMS\Serializer\SerializationContext;
/* Necessary include to enbale max depth */
$users = $this
->getDoctrine()
->getManager()
->getRepository("FooBundle:User")
->findAll();
$serializer = $this->container->get('jms_serializer');
$jsonContent = $serializer
->serialize(
$users,
'json',
SerializationContext::create()
->enableMaxDepthChecks()
);
return new Response($jsonContent);
If you are using Symfony 2.7 or above, and don't want to include any additional bundle for serializing, maybe you can follow this way to seialize doctrine entities to json -
In my (common, parent) controller, I have a function that prepares the serializer
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactory;
use Symfony\Component\Serializer\Mapping\Loader\AnnotationLoader;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Serializer;
// -----------------------------
/**
* #return Serializer
*/
protected function _getSerializer()
{
$classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
$normalizer = new ObjectNormalizer($classMetadataFactory);
return new Serializer([$normalizer], [new JsonEncoder()]);
}
Then use it to serialize Entities to JSON
$this->_getSerializer()->normalize($anEntity, 'json');
$this->_getSerializer()->normalize($arrayOfEntities, 'json');
Done!
But you may need some fine tuning. For example -
If your entities have circular reference, check how to handle it.
If you want to ignore some properties, can do it
Even better, you can serialize only selective attributes.
When you need to create a lot of REST API endpoints on Symfony,
the best way is to use the following stack of bundles:
JMSSerializerBundle for the serialization of Doctrine entities
FOSRestBundle bundle for response view listener. Also, it can generate definitions of routes based on controller/action name.
NelmioApiDocBundle to auto-generate online documentation and Sandbox(which allows testing endpoint without any external tool).
When you configure everything properly, you entity code will look like this:
use Doctrine\ORM\Mapping as ORM;
use JMS\Serializer\Annotation as JMS;
/**
* #ORM\Table(name="company")
*/
class Company
{
/**
* #var string
*
* #ORM\Column(name="name", type="string", length=255)
*
* #JMS\Expose()
* #JMS\SerializedName("name")
* #JMS\Groups({"company_overview"})
*/
private $name;
/**
* #var Campaign[]
*
* #ORM\OneToMany(targetEntity="Campaign", mappedBy="company")
*
* #JMS\Expose()
* #JMS\SerializedName("campaigns")
* #JMS\Groups({"campaign_overview"})
*/
private $campaigns;
}
Then, code in controller:
use Nelmio\ApiDocBundle\Annotation\ApiDoc;
use FOS\RestBundle\Controller\Annotations\View;
class CompanyController extends Controller
{
/**
* Retrieve all companies
*
* #View(serializerGroups={"company_overview"})
* #ApiDoc()
*
* #return Company[]
*/
public function cgetAction()
{
return $this->getDoctrine()->getRepository(Company::class)->findAll();
}
}
The benefits of such a set up are:
#JMS\Expose() annotations in the entity can be added to simple fields, and to any type of relations. Also, there is the possibility to expose the result of some method execution (use annotation #JMS\VirtualProperty() for that)
With serialization groups, we can control exposed fields in different situations.
Controllers are very simple. The action method can directly return an entity or array of entities, and they will be automatically serialized.
And #ApiDoc() allows testing the endpoint directly from the browser, without any REST client or JavaScript code
Now you can also use Doctrine ORM Transformations to convert entities to nested arrays of scalars and back
The accepted answer is correct but if You'll need to serialize a filtered subset of an Entity , json_encode is enough:
Consider this example:
class FileTypeRepository extends ServiceEntityRepository
{
const ALIAS = 'ft';
const SHORT_LIST = 'ft.name name';
public function __construct(ManagerRegistry $registry)
{
parent::__construct($registry, FileType::class);
}
public function getAllJsonFileTypes()
{
return json_encode($this->getAllFileTypes());
}
/**
* #return array
*/
public function getAllFileTypes()
{
$query = $this->createQueryBuilder(self::ALIAS);
$query->select(self::SHORT_LIST);
return $query->getQuery()->getResult();
}
}
/** THIS IS ENOUGH TO SERIALIZE AN ARRAY OF ENTITIES SINCE the doctrine SELECT will remove complex data structures from the entities itself **/
json_encode($this->getAllFileTypes());
Short note: Tested at least on Symfony 5.1

removeElement() and clear() doesn't work in doctrine 2 with array collection property

I'm trying to get some simple CRUD done with doctrine 2 but when it's time to update a record with one property set as an array collection I don't seem to get removeElement() to work as it's supposed to. I even tried doing it in this ridiculously ugly way:
foreach($entity->getCountries() as $c) {
$entity->getCountries()->removeElement($c);
$this->em->persist($entity);
$this->em->flush();
}
and it didn't work... Anyone knows how to handle this? I've asked for a solution to this in many different forms and haven't got a good response so far... seems there's lack of good examples of Doctrine 2 CRUD handling. I'll post more code at request.
Edit
//in user entity
/**
*
* #param \Doctring\Common\Collections\Collection $property
* #OneToMany(targetEntity="Countries",mappedBy="user", cascade={"persist", "remove"})
*/
private $countries;
//in countries entity
/**
*
* #var User
* #ManyToOne(targetEntity="User", inversedBy="id")
* #JoinColumns({
* #JoinColumn(name="user_id", referencedColumnName="id")
* })
*/
private $user;
I do something similar in a project with Events which have participants not unlike your User/Country relationship. I will just lay out the process and you can see if there's anything you are doing differently.
On the Participant entity
/**
* #ManyToOne(targetEntity="Event", inversedBy="participants", fetch="LAZY")
* #JoinColumn(name="event_id", referencedColumnName="id", nullable="TRUE")
* #var Event
*/
protected $event;
On the Event entity:
/**
* #OneToMany(targetEntity="Participant", mappedBy="event")
* #var \Doctrine\Common\Collections\ArrayCollection
*/
protected $participants;
Also in Event#__constructor I initialize like this:
$this->participants = new \Doctrine\Common\Collections\ArrayCollection();
Here is how I update an event:
public function update(Event $event, Event $changes)
{
// Remove participants
$removed = array();
foreach($event->participants as $participant)
{
if(!$changes->isAttending($participant->person))
{
$removed[] = $participant;
}
}
foreach($removed as $participant)
{
$event->removeParticipant($participant);
$this->em->remove($participant);
}
// Add new participants
foreach($changes->participants as $participant)
{
if(!$event->isAttending($participant->person))
{
$event->addParticipant($participant);
$this->em->perist($participant);
}
}
$event->copyFrom($changes);
$event->setUpdated();
$this->em->flush();
}
The methods on the Event entity are:
public function removeParticipant(Participant $participant)
{
$this->participants->removeElement($participant);
$participant->unsetEvent();
}
public function addParticipant(Participant $participant)
{
$participant->setEvent($this);
$this->participants[] = $participant;
}
The methods on the Participant entity are:
public function setEvent(Event $event)
{
$this->event = $event;
}
public function unsetEvent()
{
$this->event = null;
}
UPDATE: isAttending method
/**
* Checks if the given person is a
* participant of the event
*
* #param Person $person
* #return boolean
*/
public function isAttending(Person $person)
{
foreach($this->participants as $participant)
{
if($participant->person->id == $person->id)
return true;
}
return false;
}
New answer
In your countries entity, should you not have:
#ManyToOne(targetEntity="User", inversedBy="countries")
instead of inversedBy="id"?
Initial answer
You need to set the countries field in your entity as remove cascade. For example, on a bidirectional one to many relationship:
class Entity
{
/**
*
* #OneToMany(targetEntity="Country", mappedBy="entity", cascade={"remove"})
*/
private $countries;
}
This way, when saving your entity, doctrine will also save changes in collections attached to your entity (such as countries). Otherwise you have to explicitly remove the countries you want to remove before flushing, e.g.
$this->em()->remove($aCountry);
This is also valid for persist, merge and detach operations. More information here.

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