Doctrine 2.1 - Removing from collection - php

Question

I am trying to remove comments from a parent entity, I remember doing this on my last website but now it's not working..
My entity - users
namespace Application\Entities;
use Doctrine\ORM\Mapping AS ORM,
Doctrine\Common\Collections\ArrayCollection;
/**
* Loan
*
* #ORM\Table(name="users")
* #ORM\Entity
*/
class Users{
/**
* #var integer $id
*
* #ORM\Column(type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #var string $username
*
* #ORM\Column(type="string", length=45, nullable=false)
*/
private $username;
/**
* #var ArrayCollection
*
* #ORM\OneToMany(targetEntity="Comments", mappedBy="author", cascade={"persist", "remove"})
*/
private $comments;
public function getComments(){
return $this->comments;
}
and my comments table:
namespace Application\Entities;
use Doctrine\ORM\Mapping AS ORM,
Doctrine\Common\Collections\ArrayCollection;
/**
* Loan
*
* #ORM\Table(name="comments")
* #ORM\Entity
*/
class Comments{
/**
* #var integer $id
*
* #ORM\Column(type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #var integer $user_id
*
* #ORM\Column(type="integer", length=15, nullable=false)
*/
private $user_id
/**
* #var Loan
*
* #ORM\ManyToOne(targetEntity="Users", inversedBy="comments",cascade={"persist"})
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="user_id", referencedColumnName="id")
* })
*/
private $author;
This is fine, it works and I get all collections called comments in the users repository..
Now, I usually do this when I need to delete:
$commentToDelete = $this->em->getRepository('Entities\Comments')->findOneById(375);
$userResults = $this->em->getRepository('Entities\Users')->findOneById(23);
$userResults->getComments()->removeElement($commentToDelete);
$this->em->flush();
Nothing deletes, neither it throws an exception to tell me it hasn't.
I doctrine flushed it too, checked the db, and it's still there..
UPDATE:
Straight after I removeElement, I looped through the user id = 23 dataset, and the comment data for id375 is not there... so it removed it from the collection but not from the DB, and I thought $em->flush() is supposed to do this?
Please advise
Thanks

Answer 1

You need to use
$em->remove($commentToDelete);
$em->flush();
Because the mapping is held in the comment you need to remove this entity to remove the reference before you flush which will save the state to the db.