Symfony2 remove and save many to many relations
many-to-many, persist, php, symfony, symfony-2.1
Solution
In order to remove an item from a collection use the following:
$collection->removeElement($item);
The `remove($key)` function will remove by key while `removeElement($item)` removes the item from the collection if found. Have a look at the ArrayCollection code here.
Be aware that doctrine will only check the owning side of a relation for changes.
Problem
I need your help today. I'm working on a small application using Symfony 2.1 but I have a base problem, I have to tables with a many to many relation which creates a third table: ``` class Usuario implements UserInterface { /** * @ORM\ManyToMany(targetEntity="Alood\BackBundle\Entity\Alergeno", inversedBy="usuarios") * @ORM\JoinTable(name="UsuariosProductos", * joinColumns={@ORM\JoinColumn(name="usuario_user", referencedColumnName="user")}, * inverseJoinColumns={@ORM\JoinColumn(name="alergeno_id", referencedColumnName="id")} * ) **/ protected $alergenos; } public function __construct(){ $this->alergenos = new ArrayCollection(); } public function getAlergenos() { return $this->alergenos; } ``` and: ``` /** * @ORM\ManyToMany(targetEntity="Alood\BackBundle\Entity\Usuario", mappedBy="alergenos") **/ protected $usuarios; ``` Then I need to remove the non selected Alergenos, this is my controller: ``` $alergenosUser = $em->getRepository("BackBundle:Usuario")->find($usuario); $resultSym = array_diff($alergenosUsuarioIds, $alergen); foreach($resultSym as $result) { $alergenosUser->getAlergenos()->remove($result); } $em->persist($alergenosUser); $em->flush(); ``` Could you please help me to figure out what I'm doing wrong? Thanks you so much!