Saving information in controller symfony relation ManyToMany HELPPPPP - symfony

Question

Hi I need to save information in my db, what I mean is, how to persist when the relationship is manytomany, I am doing like this but it doesn't work!...I will put some code of entity Menu.
/** Agrega nuevo menù
*
* #Route("/save", name="admin_menu_save")
* #Method({"GET", "POST"})
* #param Request $request
* #return Response
*/
public function saveAction(Request $request)
{
$em = $this->getDoctrine()->getManager();
$fecha_menu = $request->get('fecha');
$fecha_comprar = $request->get('fechacomprado');
$fecha_vencimiento = $request->get('fechavencimiento');
$alimentos = $request->get('select_alimentos');
$a = $em->getRepository('AdminBundle:Alimento')->findBy($alimentos);
$menu = new Menu();
$menu->setFecha(new \DateTime($fecha_menu));
$menu->setFechacomprar(new \DateTime($fecha_comprar));
$menu->setFechavence(new \DateTime($fecha_vencimiento));
$menu->setPrecio(6);
$menu->addAlimento($a);
$em->persist($menu);
$em->flush();
return new Response('Guardado OK');
}
//Menu Entity Definition (Just the necessary code):
/**
* #ORM\ManyToMany(targetEntity="Alimento", inversedBy="menu")
* #ORM\JoinTable(name="alimento_menu",
* joinColumns={
* #ORM\JoinColumn(name="menu_id", referencedColumnName="id")
* },
* inverseJoinColumns={
* #ORM\JoinColumn(name="alimento_id", referencedColumnName="id")
* }
* )
*/
private $alimento;
/**
* Constructor
*/
public function __construct()
{
$this->alimento = new ArrayCollection();
}
/**
* Add alimento
*
* #param \AdminBundle\Entity\Alimento $alimento
*
* #return Menu
*/
public function addAlimento(Alimento $alimento)
{
$this->alimento[] = $alimento;
return $this;
}
/**
* Remove alimento
*
* #param \AdminBundle\Entity\Alimento $alimento
*/
public function removeAlimento(Alimento $alimento)
{
$this->alimento->removeElement($alimento);
}
/**
* Get alimento
*
* #return ArrayCollection
*/
public function getAlimento()
{
return $this->alimento;
}
}
I have not experience working with manytomany relations, I hope to solve this problem, that´s show very good, but I don´t know how to save,edit or remove in that manytomany table!....

Answer 1

First, this bit seems weird.
$alimentos = $request->get('select_alimentos');
$a = $em->getRepository('AdminBundle:Alimento')->findBy($alimentos);
Doctrine findBy takes an array with the entity field as a key and the specific entity value as the value. Like this:
$em-getRepository('AdminBundle:Alimento')->findBy(['id' => $id]);
If that's how your $alimentos variable is structured, that's fine. It just looks strange.
If this is a bi-directional relationship, you have to update both entities. So your controller code is like:
$a = $em->getRepository('AdminBundle:Alimento')->findBy($alimentos);
$menu = new Menu();
// -- more code ---//
$menu->addAlimento($a);
$a->addMenu($menu);
$em->persist($menu);
$em->flush();
Check this documentation.

Answer 2

I just realized what was...This was my solution:
foreach ($alimentos as $item) {
$a = $em->getRepository('AdminBundle:Alimento')->find($item);
$menu->addAlimento($a);
}
And of course later I persist menu.