SQLSTATE[23000]: Integrity constraint violation: 19 NOT NULL constraint failed

Ao fazer os exercícios do capítulo 4, Relacionamento ManyToMany, me deparo com este erro quando tento inserir um aluno com telefone.

An exception occurred while executing a query: SQLSTATE[23000]: Integrity constraint violation: 19 NOT NULL constraint failed: Phone.phoneNumber#0 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\dbal\src\Connection.php(1822): Doctrine\DBAL\Driver\API\SQLite\ExceptionConverter->convert(Object(Doctrine\DBAL\Driver\PDO\Exception), Object(Doctrine\DBAL\Query))

#1 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\dbal\src\Connection.php(1763): Doctrine\DBAL\Connection->handleDriverException(Object(Doctrine\DBAL\Driver\PDO\Exception), Object(Doctrine\DBAL\Query))

#2 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\dbal\src\Statement.php(193): Doctrine\DBAL\Connection->convertExceptionDuringQuery(Object(Doctrine\DBAL\Driver\PDO\Exception), 'INSERT INTO Pho...', Array, Array)

#3 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\dbal\src\Statement.php(248): Doctrine\DBAL\Statement->execute(NULL)

#4 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\orm\lib\Doctrine\ORM\Persisters\Entity\BasicEntityPersister.php(278): Doctrine\DBAL\Statement->executeStatement()

#5 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\orm\lib\Doctrine\ORM\UnitOfWork.php(1133): Doctrine\ORM\Persisters\Entity\BasicEntityPersister->executeInserts()

#6 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\orm\lib\Doctrine\ORM\UnitOfWork.php(430): Doctrine\ORM\UnitOfWork->executeInserts(Object(Doctrine\ORM\Mapping\ClassMetadata))

#7 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\vendor\doctrine\orm\lib\Doctrine\ORM\EntityManager.php(403): Doctrine\ORM\UnitOfWork->commit(NULL)

#8 C:\Users\bruno\eclipse-workspace 2\php-pdo-projeto-inicial\bin\insert-student.php(16): Doctrine\ORM\EntityManager->flush()

#9 {main}

Seguem os códigos escritos.

Classe Student

<?php

namespace Bruno\Doctrine\Domain\Model;

use Doctrine\ORM\Mapping\Entity;
use Doctrine\ORM\Mapping\Id;
use Doctrine\ORM\Mapping\GeneratedValue;
use Doctrine\ORM\Mapping\Column;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;

#[Entity]
class Student
{
    #[Id, GeneratedValue, Column]
    private int $id;

    #[Column]
    private string $name;

    #[OneToMany(Phone::class,"students")]
    public Collection $phones;

    public function __construct(string $name)
    {
        $this->name = $name;
        $this->phones = new ArrayCollection();
    }

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

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

    public function changeName(string $name): void
    {
        $this->name = $name;
    }

    public function addPhone(Phone $phone): void
    {
        $this->phones->add($phone);
        $phone->setStudent($this);
    }

    public function phones(): iterable
    {
        return $this->phones;
    }
}

Classe Phone

<?php
namespace Bruno\Doctrine\Domain\Model;
use Doctrine\ORM\Mapping\Entity;
use Doctrine\ORM\Mapping\Id;
use Doctrine\ORM\Mapping\GeneratedValue;
use Doctrine\ORM\Mapping\Column;

#[Entity]
class Phone
{
    #[Id, GeneratedValue, Column]
    private int $id;

    #[Column]
    private string $phoneNumber;

    #[ManyToOne(Student::class, "student", "phones")]
    private Student $student;

    public function __construct(string $phoneNumber)
    {
        $this->$phoneNumber = $phoneNumber;
    }

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

    public function getPhoneNumber(): string
    {
        return $this->$phoneNumber;
    }

    public function setStudent (Student $student): void
    {
        $this->student = $student;
    }
}

Binário insert-student.php

<?php
use Bruno\Doctrine\Domain\Model\Student;
use Bruno\Doctrine\Infrastructure\Helper\EntityManagerCreator;
use Bruno\Doctrine\Domain\Model\Phone;

require_once __DIR__ . '/../vendor/autoload.php';

$entityManager = EntityManagerCreator::createEntityManager();

$phone1 = new Phone("11 97116-0689");
$entityManager->persist($phone1);
$student = new Student("Novo Estudante");
$student->addPhone($phone1);
$entityManager->persist($student);
try{
    $entityManager->flush();
    echo "Tudo certo";
}catch (Exception $e){
    echo $e->getMessage();
    echo $e->getTraceAsString();
}

O que deu errado?