doctrine2 many to many self referencing with intermediate details

Question

I would like to create a self-referencing entity, but with a description (and possibly other information) about the relationship. An example of this would be friends in a social network application - Person A (entity) can link with Person B (entity), however their relationship could be described as "friend" "brother" "uncle" etc.

From the Doctrine documentation a class can be self referencing with a link table using the following:

<?php
/** @Entity */
class User
{
    // ...

    /**
     * @ManyToMany(targetEntity="User", mappedBy="myFriends")
     */
    private $friendsWithMe;

    /**
     * @ManyToMany(targetEntity="User", inversedBy="friendsWithMe")
     * @JoinTable(name="friends",
     *      joinColumns={@JoinColumn(name="user_id", referencedColumnName="id")},
     *      inverseJoinColumns={@JoinColumn(name="friend_user_id", referencedColumnName="id")}
     *      )
     */
    private $myFriends;

    public function __construct() {
        $this->friendsWithMe = new \Doctrine\Common\Collections\ArrayCollection();
        $this->myFriends = new \Doctrine\Common\Collections\ArrayCollection();
    }

    // ...
}

however it doesn't seem that you can add properties using this method.

The question is, is there a way to handle this in a single class (i.e. User.php) - or would one actually have to make a "link" class - like UserLink.php? I kind of got stuck making a link class when I started on the relations:

class UserLink
{
    // ...

    /**
     * @ORM\Column(type="text", nullable=true)
     */
    protected $relationship; // being brother, uncle etc

    /**
     * @ORM\ManyToOne(targetEntity="User", inversedBy="links")
     * @ORM\JoinColumn(name="user_id", referencedColumnName="id")
     * @var type
     */
    private $user;
}

But I am not sure what happens next...?

Researching on stackoverflow I found similar questions, but more about direct linking.

Doctrine2: Best way to handle many-to-many with extra columns in reference table

Need help understanding Doctrine many to many self referencing code

mogoman mogoman · Accepted Answer · 2011-11-16T20:39:51

Solved it like this:

User.php

/**
 * @ORM\OneToMany(targetEntity="UserLink", mappedBy="user")
 */
private $relations;

UserLink.php

/**
 * @ORM\Column(type="text", nullable=true)
 */
protected $relationship;

/**
 * @ORM\ManyToOne(targetEntity="User", inversedBy="relations")
 * @ORM\JoinColumn(name="user_ud", referencedColumnName="id")
 */
protected $user;

/**
 * @ORM\ManyToOne(targetEntity="User")
 * @ORM\JoinColumn(name="related_user_id", referencedColumnName="id")
 */
protected $relateduser;

It requires a bit more code in the controller and model, but works quite well. It enables the user to call getRelations:

{% for link in user.relations %}
    {{ link.relateduser.name }} ({{ link.relationship }})
{% endfor %}

doctrine2 many to many self referencing with intermediate details

1 Answers