Symofny2 n-m relationship with extra field - php

Question

I have two tables (test and question) and the middle table (n-m). In this point all works fine.
But now, I need to put extra information in the (n-m) table, the order of this question in this test
I need this:
id | test_id | question_id | order
1 | 1 | 1 | 3
2 | 1 | 2 | 2
3 | 1 | 3 | 1
4 | 1 | 4 | 4
All these relationship have made with doctrine annotation...
Test Entity
/**
* #ORM\ManyToMany(targetEntity="Question", inversedBy="tests")
*/
private $questions;
Question Entity
/**
* #ORM\ManyToMany(targetEntity="Test", mappedBy="questions"))
*/
private $tests;
Any help will be appreciated
EDIT
Hi again!
Thanks a lot to #DonCallisto
my entities at the end:
Test
/**
* #ORM\OneToMany(targetEntity="RTestQuestion", mappedBy="question")
*/
private $questions;
Question
/**
* #ORM\OneToMany(targetEntity="RTestQuestion", mappedBy="test"))
*/
private $tests;
My new entity "RTestQuestion"
/**
* ET\BackendBundle\Entity\RTestQuestion
*
* #ORM\Table(name="rtest_question")
* #ORM\Entity
*/
class RTestQuestion {
/**
* #var integer $id
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\ManyToOne(targetEntity="Question", inversedBy="questions", cascade={"persist", "remove"})
*/
private $question;
/**
* #ORM\ManyToOne(targetEntity="Test", inversedBy="tests", cascade={"persist", "remove"})
*/
private $test;
/**
* #var integer $order
*
* #ORM\Column(name="question_order", type="integer", nullable=true)
*/
private $question_order;
I had to make two changes:
The properties need the cascade on persist and remove actions (doctrine console show errors without this)
And the word "order" are restricted for mysql, and now become a question_order.
And, again, thanks to #DonCallisto!

Answer 1

Split the relationship into a 1-n and m-1 as follows
Test Entity --- (1 - m) ---> RTestQuestion Entity <--- (m - 1) --- Question
So your code will be
Test Entity
/**
* #ORM\OneToMany(targetEntity="RTestQuestion", inversedBy="question")
*/
private $questions;
Question Entity
/**
* #ORM\OneToMany(targetEntity="RTestQuestion", mappedBy="test"))
*/
private $tests;
RTestQuestion Entity
/**
* #ORM\ManyToOne(targetEntity="Question", mappedBy="questions"))
*/
private $question;
/**
* #ORM\ManyToOne(targetEntity="Test", mappedBy="tests"))
*/
private $test;
/**
* EXTRA ATTRIBUTES HERE
*/
Remember that an association with extra fields isn't an association anymore but a new entity!