Doctrine 2 not persisting the relation from owning side one to Many - php

Question

I have this code
// ONE to many Bidir -- inverse side
/**
* #ORM\OneToMany(targetEntity="Item", mappedBy="Room", cascade={"persist"})
**/
protected $items;
The other side
// ONE to many Bidir-- own side
/**
* #ORM\ManyToOne(targetEntity="Room", inversedBy="items")
* #ORM\JoinColumn(name="room_id", referencedColumnName="id")
**/
protected $room;
My Problem is that i go to item page and i select Room , then i can see items preselecetd in Room page
But if i go to Room page and i try to multiselect many items , then those are not persisted
EDIT: I have seen that it is only happening for OneToMany relation ship. For Manyto Many they are working fine
EDIT2:
I am talking about the backend area where i have the form and select box where i can select multiple items. This form/CRUD code / controllers are genrated by doctrine. SO i don't need to add any extra function. Any way this is my controller code
$editForm = $this->createForm(new RoomType(), $entity);
$request = $this->getRequest();
$editForm->bindRequest($request);
if ($editForm->isValid()) {
$em->persist($entity);
$em->flush();
When i try to walk through in controller like this
foreach($entity->getItems() as $item)
echo $item;
Then i can see all thye items there. So it means all items are there in main object but its not persisting them. i don't know why.
If there is owing , reverse side problem. How can i chnage the relationship from owing to inverse and inverse to owning

Answer 1

Your code is wrong, based on your comments in annotations.
This is the owning side, because you specify the inversedBy attribute:
/**
* ONE to many Bidir-- Inverse side
* #ORM\ManyToOne(targetEntity="Room", inversedBy="items")
* #ORM\JoinColumn(name="room_id", referencedColumnName="id")
**/
protected $room;
This is the inverse side (because it has the mappedBy attribute):
/**
* ONE to many Bidir -- owning side
* #ORM\OneToMany(targetEntity="Item", mappedBy="Room", cascade={"persist"})
**/
protected $items;
So your code says: Item is the owning side, Room is the inverse side.
The owning side of a bidirectional relationship must refer to its
inverse side by use of the inversedBy attribute of the OneToOne,
ManyToOne, or ManyToMany mapping declaration. The inversedBy attribute
designates the field in the entity that is the inverse side of the
relationship.
To make it more clean:
The owning side has to use the inversedBy attribute of the OneToOne,
ManyToOne, or ManyToMany mapping declaration. The inversedBy attribute
contains the name of the association-field on the inverse-side.
While, for the inverse side:
The inverse side of a bidirectional relationship must refer to its
owning side by use of the mappedBy attribute of the OneToOne,
OneToMany, or ManyToMany mapping declaration. The mappedBy attribute
designates the field in the entity that is the owner of the
relationship.
And, again:
The inverse side has to use the mappedBy attribute of the OneToOne,
OneToMany, or ManyToMany mapping declaration. The mappedBy attribute
contains the name of the association-field on the owning side.
Plus, another important consideration:
ManyToOne is always the owning side of a bidirectional assocation.
OneToMany is always the inverse side of a bidirectional assocation
Thus, for persisting items from the inverse side (room), you have to check which item has been selected/deselected and if room already contains that item or not.

Answer 2

Just use you loop to set room. Item is owing side and you editing inverse side (room).
Symfony2 never updates owing sides while editing inverse one.
The simplest solution for you is use loop before persisting room:
foreach($entity->getItems() as $item){
$item->setRoom($room);
}
and cascade on inverse side:
/**
* #ORM\OneToMany(targetEntity="Item", mappedBy="Room", cascade={"persist"})
**/
protected $items;
For my projects I made reusable solution based on collection events listeners.
If you have time & skills I encourage you to do the same