Relation One to Many return empty object - php

Question

I have a Evaluation entity which has one Product and Product which can have several Evaluations. I'm trying to fetch one Product and to get the list of Evaluations associated with my entity
Produit.php
<?php
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use phpDocumentor\Reflection\Types\This;
/**
* Produit
*
* #ORM\Table(name="produit", indexes={#ORM\Index(name="fk_idcatedel", columns={"idCategorie"})})
* #ORM\Entity
*/
class Produit
{
/**
* #var int
*
* #ORM\Column(name="id", type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #var string|null
*
* #ORM\Column(name="libelle", type="string", length=20, nullable=true)
*/
private $libelle;
/**
* #var float|null
*
* #ORM\Column(name="prix", type="float", precision=10, scale=0, nullable=true)
*/
private $prix;
/**
* #var string|null
*
* #ORM\Column(name="description", type="string", length=50, nullable=true)
*/
private $description;
/**
* #var int
*
* #ORM\Column(name="qt", type="integer", nullable=false)
*/
private $qt;
/**
* #var string|null
*
* #ORM\Column(name="img", type="string", length=255, nullable=true)
*/
private $img;
/**
* #var \Categorie
*
* #ORM\ManyToOne(targetEntity="Categorie")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="idCategorie", referencedColumnName="id")
* })
*/
private $idcategorie;
/**
* #ORM\OneToMany(targetEntity="Evaluation", mappedBy="idProduit")
*/
private $rates;
public function __construct()
{
$this->rates = new ArrayCollection();
}
public function getId(): ?int
{
return $this->id;
}
public function getLibelle(): ?string
{
return $this->libelle;
}
public function setLibelle(?string $libelle): self
{
$this->libelle = $libelle;
return $this;
}
public function getPrix(): ?float
{
return $this->prix;
}
public function setPrix(?float $prix): self
{
$this->prix = $prix;
return $this;
}
public function getDescription(): ?string
{
return $this->description;
}
public function setDescription(?string $description): self
{
$this->description = $description;
return $this;
}
public function getQt(): ?int
{
return $this->qt;
}
public function setQt(int $qt): self
{
$this->qt = $qt;
return $this;
}
public function getImg(): ?string
{
return $this->img;
}
public function setImg(?string $img): self
{
$this->img = $img;
return $this;
}
public function getIdcategorie(): ?Categorie
{
return $this->idcategorie;
}
public function setIdcategorie(?Categorie $idcategorie): self
{
$this->idcategorie = $idcategorie;
return $this;
}
/**
* #return Collection|Evaluation[]
*/
public function getRates(): Collection
{
return $this->rates;
}
}
Evaluation.php
<?php
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* Evaluation
*
* #ORM\Table(name="evaluation", indexes={#ORM\Index(name="fk_idprodevaldel", columns={"id_produit"}), #ORM\Index(name="fk_iduser", columns={"id_user"})})
* #ORM\Entity
*/
class Evaluation
{
/**
* #var int
*
* #ORM\Column(name="id", type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #var int
*
* #ORM\Column(name="note", type="integer", nullable=false)
*/
private $note;
/**
* #var \Produit
*
* #ORM\ManyToOne(targetEntity="Produit", inversedBy="rates")
* #ORM\JoinColumn(name="id_produit", referencedColumnName="id")
*/
private $idProduit;
/**
* #var \Compte
*
* #ORM\ManyToOne(targetEntity="Compte")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="id_user", referencedColumnName="email")
* })
*/
private $idUser;
public function getId(): ?int
{
return $this->id;
}
public function getNote(): ?int
{
return $this->note;
}
public function setNote(int $note): self
{
$this->note = $note;
return $this;
}
public function getIdProduit(): ?Produit
{
return $this->idProduit;
}
public function setIdProduit(?Produit $idProduit): self
{
$this->idProduit = $idProduit;
return $this;
}
public function getIdUser(): ?Compte
{
return $this->idUser;
}
public function setIdUser(?Compte $idUser): self
{
$this->idUser = $idUser;
return $this;
}
}
The database
In my controller I succeed to get informations from the products but rates are empty
$produits = $this->getDoctrine()
->getRepository(Produit::class)
->find(1);
dump($produits);
$rates = $produits->getRates();
dump($rates); // #collection: ArrayCollection is empty
The Output :

Answer 1

The collection is not yet initialized due to lazy loading, and rightfully so. If you don't access at least to an element in the collection, it's pointless to load the whole collection because doctrine can safely assume you'll "discard" it. As soon as you access an element (either by looping onto collection or getting a specific element), the collection will be initialized and you have all items.
Another way is to use an EAGER fetch that will load the whole collection in the hydration phase. I would not reccomend it however, unless you're sure that everytime you load a Produit, you need this collection "ready". Even in the latter case, I would handle the collection "manually" as I recommend not to lose control on it (let's pretend you have A LOT of element inside it).
Read more about proxies and association, here