adding created timestamp to join table in doctrine2 - php

Question

I have the following property in my User entity to track followers and following. Basically a user can follow other user as well. I have a join column called app_user_follow_user, however I also wanted to add a timestamp of whenever someone follows another user, when did it happen. How can I specify a created timestamp via this ORM?
/**
* #ORM\ManyToMany(targetEntity="User", mappedBy="following")
*/
protected $followers;
/**
* #ORM\ManyToMany(targetEntity="User", inversedBy="followers")
* #ORM\JoinTable(name="app_user_follow_user",
* joinColumns={#ORM\JoinColumn(name="user_id", referencedColumnName="id")},
* inverseJoinColumns={#ORM\JoinColumn(name="follow_user_id", referencedColumnName="id")}
* )
*/
protected $following;

Answer 1

Doctrine ManyToMany relationships are used when your join table has two columns. If you need to add another column you have to convert the relationship to OneToMany on both sides and ManyToOne on the joined entity.
This is entirely untested but it will hopefully give you the gist.
User Entity
/**
* #ORM\OneToMany(targetEntity="AppUserFollowUser", mappedBy="appUser")
*/
protected $followers;
/**
* #ORM\OneToMany(targetEntity="AppUserFollowUser", mappedBy="followUser")
*/
protected $following;
AppUserFollowUser Entity
/**
* #ORM\Table(name = "app_user_follow_user")
*/
class AppUserFollowUser
{
/**
* #ORM\Id
* #ORM\ManyToOne(targetEntity="User", inversedBy="followers")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="user_id", referencedColumnName="id")
* })
*/
private $appUser;
/**
* #ORM\Id
* #ORM\ManyToOne(targetEntity="User", inversedBy="following")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="follow_user_id", referencedColumnName="id")
* })
*/
private $followUser;
/**
* #ORM\Column(name="created_date", type="datetime", nullable=false)
*/
private $createdDate;
}

Answer 2

I think that you will have to create a link entity manually (entiy1 onetomany linkEntity manytoone entity2.
Because, the usual link entity are automated and should be as simple and (data less) as possible, so doctrine can take all the controle over it,
imagine you need to get the timestamp, how can you do it on an (none hard coded) entity, you will need a getter, and the annotations are not supposed to contains code.