Missing value for primary key id on App\Entity symfony - symfony

Question

My relation between 2 entities is a OneToOne relation.
1) User Entity:
<?php
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity(repositoryClass="App\Repository\UserRepository")
*/
class User
{
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
private $id;
/**
* #var $userContact
*
* #ORM\OneToOne(targetEntity="UserContact" , inversedBy="User")
* #ORM\JoinColumn(name="id", referencedColumnName="user_id", nullable=false)
**/
private $userContact;
/**
* #ORM\Column(type="string", length=255)
*/
private $last_name;
public function getId()
{
return $this->id;
}
public function getLastName(): ?string
{
return $this->last_name;
}
public function setLastName(string $last_name): self
{
$this->last_name = $last_name;
return $this;
}
}
UserContact Entity:
class UserContact
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id()
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(type="integer")
*/
private $user_id;
/**
* #ORM\OneToOne(targetEntity="User", inversedBy="UserContact")
*/
private $user;
/**
* #ORM\Column(type="string", length=255)
*/
private $mobile_number;
public function getId()
{
return $this->id;
}
public function getUserId(): ?int
{
return $this->user_id;
}
public function setUserId(int $user_id): self
{
$this->user_id = $user_id;
return $this;
}
public function getMobileNumber(): ?string
{
return $this->mobile_number;
}
public function setMobileNumber(string $mobile_number): self
{
$this->mobile_number = $mobile_number;
return $this;
}
}
My User Repository looks like this:
class UserRepository extends ServiceEntityRepository
{
public function index() {
return $this->createQueryBuilder('u')
->innerJoin('u.userContact', 'uc')
->getQuery()
->execute();
}
}
And the controller looks like this:
public function index()
{
$users = $em->getRepository('App:User')->index();
}
It's throwing an error like this one:
Missing value for primary key id on App\Entity\UserContact

Answer 1

In your association, the owning side is User and the inverse side is UserContact. You must use mappedBy for the inverse side instead inversedBy. So your annotation for the $user attribute in User entity must be this:
/**
* #ORM\OneToOne(targetEntity="User", mappedBy="UserContact")
*/
private $user;
https://www.doctrine-project.org/projects/doctrine-orm/en/latest/reference/unitofwork-associations.html