Doctrine2 - How to remove ManyToMany associations on add of new ones - doctrine-orm

Question

I've took a quick look but can't find the answer.
Take the following entities, users who can have many roles:
/**
* #Entity
**/
class User
{
/**
* #ManyToMany(targetEntity="Role", inversedBy="users")
* #JoinTable(name="user_to_roles")
**/
protected $roles;
public function __construct()
{
$this->roles = new \Doctrine\Common\Collections\ArrayCollection();
}
public function addRole(Role $role)
{
$role->addUser($this);
$this->roles[] = $role;
}
public function getRoles()
{
return $this->roles;
}
}
and the roles:
/**
* #Entity
**/
class Role
{
/**
* #Id
* #Column(type="integer")
* #GeneratedValue(strategy="AUTO")
**/
protected $id;
/**
* #ManyToMany(targetEntity="User", mappedBy="roles")
**/
protected $users;
public function __construct()
{
$this->users = new \Doctrine\Common\Collections\ArrayCollection();
}
public function addUser(User $user)
{
$this->users[] = $user;
}
public function getUsers()
{
return $this->users;
}
}
When I want to update a user I will get the reference, and update like so:
$user = $this>entityManager->getReference('App\Entity\User', $id);
$user->addRole($role);
$this->entityManager->persist($user);
$this->entityManager->flush();
However, this will continuously add new roles to my relational table, whereas I just want to update the current row, or delete it and create a new one (whichever is easier). How can I achieve this?

Answer 1

Try to add this function to your entity:
function setRoles($roles) {
$this->roles = new ArrayCollection($roles);
}
And when you update try this:
$user = $this>entityManager->getReference('App\Entity\User', $id);
$roles = array();
// add your roles to the array roles
$user->setRoles($roles);
$this->entityManager->persist($user);
$this->entityManager->flush();