How can I output ManyToOne data with doctrine (Symfony 4)? - arrays

Question

This is my entity "data":
<?php
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity(repositoryClass="App\Repository\DataRepository")
*/
class Data
{
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
private $id;
/**
* #ORM\Column(type="string", length=10, unique=true)
*/
private $uuid;
/**
* #ORM\Column(type="string", length=255)
*/
private $content;
/**
* #ORM\ManyToOne(targetEntity="Fields")
* #ORM\JoinColumn(name="field", referencedColumnName="id")
*/
private $fields;
public function getId(): ?int
{
return $this->id;
}
public function getContent()
{
return $this->content;
}
public function setContent($content)
{
$this->content = $content;
}
public function getUuid(): ?string
{
return $this->uuid;
}
public function setUuid(string $uuid): self
{
$this->uuid = $uuid;
return $this;
}
public function getFields(): ?Fields
{
return $this->fields;
}
public function setFields(?Fields $fields): self
{
$this->fields = $fields;
return $this;
}
}
I am getting the data via doctrine:
$output = $this->em->getRepository(Data::class)->findAll();
The output:
array:2 [▼
0 => Data {#7060 ▼
-id: 1
-uuid: "12345"
-content: "blabla"
-fields: Fields {#7164 ▼
+__isInitialized__: false
-id: 6
-name: null
-uuid: null
-productgroup: null
-type: null
…2
}
}
1 => Data {#7165 ▶}
]
The problem is, that the data of the ManyToOne "fields" captures only the id. But not the name or productgroup. It is all "null". But in my database it is not null.

Answer 1

This usually happen when you are dumping objects with relations. For checking that fields relation has not null values. Do this:
dump($output[0]->getFields()->getName())

Answer 2

This is because relations from doctrine are not loaded in this case.
If you access the relation before, e.g.
$output->fields
The relation will actually be loaded and the fields won't be null if you dump it afterwards
See Relationships and Proxy Classes

Answer 3

This is cause by doctrine lazy loading, in order to avoid overloading memmory.
As #AythaNzt says, if you loop trougth entities you will be able to acces their properties (when you as for getField() doctrine trigger a query to fetch their data)
Check this to display all child fields: Avoid lazy loading Doctrine Symfony2