对于我的项目，我需要将一个或多个待办事项属性给一个或多个用户。
我的实体：

待办事项

namespace App\Entity;

    use App\Repository\TodosRepository;
    use Doctrine\Common\Collections\ArrayCollection;
    use Doctrine\Common\Collections\Collection;
    use Doctrine\DBAL\Types\Types;
    use Doctrine\ORM\Mapping as ORM;

     #[ORM\Entity(repositoryClass: TodosRepository::class)]
     class Todos
     {
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255)]
    private ?string $title = null;

    #[ORM\Column(length: 255, nullable: true)]
    private ?string $color = null;

    #[ORM\Column(type: Types::TEXT)]
    private ?string $description = null;

    #[ORM\ManyToMany(targetEntity: Users::class, inversedBy: 'todo_id')]
    private Collection $owner;

    #[ORM\Column(type: Types::DATETIME_MUTABLE)]
    private ?\DateTimeInterface $date_created = null;

    public function __construct()
    {
        $this->owner = new ArrayCollection();
    }

        
 (...)
    public function getDescription(): ?string
    {
        return $this->description;
    }

    public function setDescription(string $description): self
    {
        $this->description = $description;

        return $this;
    }

    /**
     * @return Collection<int, Users>
     */
    public function getOwner(): Collection
    {
        return $this->owner;
    }

    public function addOwner(Users $owner): self
    {
        if (!$this->owner->contains($owner)) {
            $this->owner->add($owner);
        }
        return $this;
    }

    public function removeOwner(Users $owner): self
    {
        $this->owner->removeElement($owner);

        return $this;
    }
(...)
    }

用户/所有者

namespace App\Entity;
    use App\Repository\UsersRepository;
    use Doctrine\Common\Collections\ArrayCollection;
    use Doctrine\Common\Collections\Collection;
    use Doctrine\ORM\Mapping as ORM;

    #[ORM\Entity(repositoryClass: UsersRepository::class)]
    class Users
    {
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255)]
    private ?string $name = null;

    #[ORM\ManyToMany(targetEntity: Todos::class, mappedBy: 'owner')]
    private Collection $todo_id;

    public function __construct()
    {
        $this->todo_id = new ArrayCollection();
    }

    public function getId(): ?int
    {
        return $this->id;
    }

    public function getName(): ?string
    {
        return $this->name;
    }

    public function setName(string $name): self
    {
        $this->name = $name;

        return $this;
    }

    /**
     * @return Collection<int, Todos>
     */
    public function getTodoId(): Collection
    {
        return $this->todo_id;
    }

    public function addTodoId(Todos $todoId): self
    {
        if (!$this->todo_id->contains($todoId)) {
            $this->todo_id->add($todoId);
            $todoId->addOwner($this);
        }

        return $this;
    }

    public function removeTodoId(Todos $todoId): self
    {
        if ($this->todo_id->removeElement($todoId)) {
            $todoId->removeOwner($this);
        }

        return $this;
    }
    }

我的控制器：

if ($checkItems) {
            $user = $usersRepo->findBy(array("id" => $idUser));
            $todo = $todosRepo->findBy(array("id" => $idTodo));
            $newTodo = new Todos();
            $newOwner = new Users();

            $em = $doctrine->getManager();
            $newTodo->addOwner($user[0]);
            $newOwner->addTodoId($todo[0]);
            $em->persist($newTodo);
            $em->persist($newOwner);
            $em->flush();

            return $this->redirectToRoute("app_todos");
        }

但我有一个错误消息：
执行查询时出现异常错误：数据库状态[23000]：
完整性约束冲突：1048字段'name'不能为空（null）
我不明白为什么，因为我不需要创建新的***TODO***或新的***USERS***，只需添加关系即可。
任何帮助都是受欢迎的！