Doctrine 2 Many to Many relation with additional columns in join table - php

Question

So, I have been playing round with using doctrine for a while now and have it in some basic projects, but i decided to go back and have an in depth look into what it can do.
Ive now decided to switch to symfony 2 as my framework of choice and am looking into what doctrine 2 can do in more depth.
One thing i have been trying to get my head around is the many to many relationship within doctrine. I am starting to build a recipe system and am working on the relation between recipe and ingredients which gave me 3 entities, recipe, recipeIngredient and ingredient. The reason i cannot use a direct many to many relation is because i want to store two additional columns in the join table ( unit and quantity ) for each ingredient.
The problem i am having at the moment is that the entities persist ok, but the recipe_id in the join table is not inserted. I have tried everything i can think off and been through every thread and website looking for an answer . I am sure it is something completely obvious that i am missing. Please help, below is the code i have so far:
<?php
namespace Recipe\RecipeBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
/**
* #ORM\Entity
* #ORM\Table(name="recipe")
* #ORM\HasLifecycleCallbacks()
*/
class Recipe{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue(strategy="AUTO")
*/
protected $id;
/**
* #ORM\OneToMany(targetEntity="RecipeIngredient", mappedBy="recipe", cascade= {"persist"})
*/
protected $ingredients;
/**
* #ORM\Column(type="string")
* #var string $title
*
*/
protected $title;
/**
* Constructor
*/
public function __construct()
{
$this->ingredients = new \Doctrine\Common\Collections\ArrayCollection();
}
/**
* Get id
*
* #return integer
*/
public function getId()
{
return $this->id;
}
/**
* Add ingredients
*
* #param \Recipe\RecipeBundle\Entity\RecipeIngredient $ingredients
* #return Recipe
*/
public function addIngredient(\Recipe\RecipeBundle\Entity\RecipeIngredient $ingredients)
{
$ingredients->setRecipe($this);
$this->ingredients[] = $ingredients;
return $this;
}
/**
* Remove ingredients
*
* #param \Recipe\RecipeBundle\Entity\RecipeIngredient $ingredients
*/
public function removeIngredient(\Recipe\RecipeBundle\Entity\RecipeIngredient $ingredients)
{
$this->ingredients->removeElement($ingredients);
}
/**
* Get ingredients
*
* #return \Doctrine\Common\Collections\Collection
*/
public function getIngredients()
{
return $this->ingredients;
}
/**
* Set title
*
* #param string $title
* #return Recipe
*/
public function setTitle($title)
{
$this->title = $title;
return $this;
}
/**
* Get title
*
* #return string
*/
public function getTitle()
{
return $this->title;
}
}
and recipeIngredient
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue(strategy="AUTO")
*/
protected $id;
/**
* #ORM\ManyToOne(targetEntity="Recipe", inversedBy="ingredients")
* */
protected $recipe;
/**
* #ORM\ManyToOne(targetEntity="Ingredient", inversedBy="ingredients" , cascade={"persist"})
* */
protected $ingredient;
/**
* #ORM\Column(type="string")
* #var string $quantity
*
*/
protected $quantity;
/**
* #ORM\Column(type="string")
* #var string $unit
*
*/
protected $unit;
/**
* Get id
*
* #return integer
*/
public function getId()
{
return $this->id;
}
/**
* Set quantity
*
* #param string $quantity
* #return RecipeIngredient
*/
public function setQuantity($quantity)
{
$this->quantity = $quantity;
return $this;
}
/**
* Get quantity
*
* #return string
*/
public function getQuantity()
{
return $this->quantity;
}
/**
* Set unit
*
* #param string $unit
* #return RecipeIngredient
*/
public function setUnit($unit)
{
$this->unit = $unit;
return $this;
}
/**
* Get unit
*
* #return string
*/
public function getUnit()
{
return $this->unit;
}
/**
* Set recipe
*
* #param \Recipe\RecipeBundle\Entity\Recipe $recipe
* #return RecipeIngredient
*/
public function setRecipe(\Recipe\RecipeBundle\Entity\Recipe $recipe = null)
{
$this->recipe = $recipe;
return $this;
}
/**
* Get recipe
*
* #return \Recipe\RecipeBundle\Entity\Recipe
*/
public function getRecipe()
{
return $this->recipe;
}
/**
* Set ingredient
*
* #param \Recipe\RecipeBundle\Entity\Ingredient $ingredient
* #return RecipeIngredient
*/
public function setIngredient(\Recipe\RecipeBundle\Entity\Ingredient $ingredient = null)
{
$this->ingredient = $ingredient;
return $this;
}
/**
* Get ingredient
*
* #return \Recipe\RecipeBundle\Entity\Ingredient
*/
public function getIngredient()
{
return $this->ingredient;
}
}

Answer 1

Your basic idea is the correct one. If you want to have a ManyToMany relation, but you need to add extra fields in the join table, the way to go is exactly as you have described: using a new entity having 2 ManyToOne relations and some additional fields.
Unfortunately you have not provided your controller code, because most likely your problem is there.
Basically if you do something like:
$ri = new RecipeIngredient;
$ri->setIngredient($i);
$ri->setRecipe($r);
$ri->setQuantity(1);
$em->persist($ri);
$em->flush();
You should always get a correct record in your database table having both recipe_id and ingredient_id filled out correctly.
Checking out your code the following should also work, although I personally think this is more sensitive to mistakes:
$ri = new RecipeIngredient;
$ri->setIngredient($i);
$ri->setQuantity(1);
// here we assume that Recipe->addIngredient also does the setRecipe() for us and
// that the cascade field is set correctly to cascade the persist on $ri
$r->addIngredient($ri);
$em->flush();
For further reading I would suggest the other topics on this subject, such as: Doctrine2: Best way to handle many-to-many with extra columns in reference table

Answer 2

If I understand this model correctly the construction of a recipe and its associated recipeIngredients are concurrent. You might not have an id until you persist and without an id if receipeIngredient->setRecipe() is called the default null will be place in the recipeIngredient->recipe field. This is often handled with cascade: "persist" (not present for the recipe field in your example, but you can handle it explicitly in the controller:
/**
* Creates a new Recipe entity.
*
*/
public function createAction(Request $request)
{
$em = $this->getDoctrine()->getManager();
$form = $this->createForm(new RecipeType());
$form->bind($request);
if ($form->isValid()){
$data = $form->getData();
$recipeId = $data->getId();
$recipeIngredients=$data->getIngredients();
$recipe=$em->getRepository('reciperecipeBundle:Recipe')
->findOneById($RecipeId);
if (null === $Recipe)
{$Recipe=new Recipe();}
foreach ($recipeIngredients->toArray() as $k => $i){
$recipeIngredient=$em->getRepository('reciperecipeBundle:recipeIngredient')
->findOneById($i->getId());
if (null === $recipeIngredient)
{$recipeIngrediente=new RecipeIngredient();}
$recipe->addIngredient($i);
// Next line *might* be handled by cascade: "persist"
$em->persist($recipeIngredient);
}
$em->persist($Recipe);
$em->flush();
return $this->redirect($this->generateUrl('Recipe', array()));
}
return $this->render('reciperecipeBundle:Recipe:new.html.twig'
,array('form' => $form->createView()));
}

Answer 3

Im not really sure if this would be a solution, but its easy yo try it, and probably it will help.
When I create a relationshiop of this kind, I use to write another anotation, the #ORM\JoinColumn, like in this example:
We have an entity A, an entity B, and an class AB wich represents the relationships, and adds some other fields, like in you case.
My relationship would be as follows:
use Doctrine\ORM\Mapping as ORM;
/**
*
*
* #ORM\Table(name="a_rel_b")
* #ORM\Entity
*/
class AB
{
/**
* #var integer
* #ORM\Id
* #ORM\ManyToOne(targetEntity="A", inversedBy="b")
* #ORM\JoinColumn(name="a_id", referencedColumnName="id")
**/
private $a;
/**
* #var integer
* #ORM\Id
* #ORM\ManyToOne(targetEntity="B", inversedBy="a")
* #ORM\JoinColumn(name="b_id", referencedColumnName="id")
**/
private $b;
// ...
name means the name of the field in the relationship table, while referencedColumnName is the name of the id field in the referenced entity table (i.e b_id is a column in a_rel_b that references the column id in the table B )

Answer 4

You can't, because it wouldn't be a relationship anymore [which is, by def, a subset of the cartesian product of the sets of the two original entities].
You need an intermediate entity, with references to both Recipe and Ingredient - call it RecipeElement, RecipeEntry or so, and add the fields you want.
Either, you can add a map to your Recipe, in which you save the attributes for each Ingredient you save, easy to maintain if there are no duplicates.
For further reading, have a look at this popular question.