将EntityType选项保存为字符串 - Symfony 4

I have entity1 and entity2.

In the entity1's form, I am displaying a choice list where the options are comming from entity2. I want to save the selected choice as string inside a column in entity1's table, but I dont want to create any relations between the tables.

How Should I do that?

class Entity1 {
/**
 * @ORM\Column(type="string")
 */
private $historico;
}

class Entity2 {
/**
 * @ORM\Column(type="string")
 */
private $description;
}

Entity1FormType.php

$builder->add('historico', EntityType::class, [
                'class' => Entity2::class,
                'choice_label' => 'description',
                'choice_value' => 'description',
                'placeholder' => ''
            ]);

The choices display fine, but when I submit I get the following error:

Expected argument of type "string", "App\Entity\Entity2" given.

If I use 'mapped' => false, the input submit as null.

How do I convert the entity object to string? Help a symfony noob :)

If you use mapped => false you have to fetch the data manually in your controller after the form is submitted.

so you will have something like this:

public function postYourFormAction(Request $request)
{
    $entity1 = new Entity1();
    $form = $this->createForm(Entity1Type::class $entity1);
    $form->handleRequest($request);
    if($form->isSubmitted() && $form->isValid()) {
        $entity1 = $form->getData;
        $historico = $form->get('historico')->getData();
        $entity1->setHistorico($historico);
        $em->persist($entity1);
        $em->flush();
    }
}