Symfony 4 / Sonata: create a ManyToMany administration

We will develop here all the manipulations to build a many to many interface via Sonata.
We will take as an example a zone management with a connection by departments. Each zone is thus constituted of multiple connections with the department table.

In MysqlWorkbench, it looks like this:

To generate the entities, we use the following command:

php bin/console doctrine:mapping:import "App\Entity" annotation --path=src/Entity

Next, we create the setters and getters in our entities using the command:

php bin/console make:entity --regenerate App

Now all that's left is to generate our Sonata CRUD without forgetting to clear the cache.

php bin/console make:sonata:admin App/Entity/ZxZone
php bin/console cache:clear

Our interface will be created and the service as well. We will still have to perform a few manipulations.

1 – Remove the ID from our record creation form and add our department field

//ajouter le use suivant
use Symfony\Bridge\Doctrine\Form\Type\EntityType;

//supprimez l'id, et ajouter la liaison département
  protected function configureFormFields(FormMapper $formMapper): void
    {
       $formMapper
           //->add('id')
            ->add('label')
            ->add('code')
            ->add('departement', EntityType::class, [
                'class' => 'App\Entity\Departement',
                'choice_label' => 'label',
                'label' => 'Départements',
                'required' => false,
                'by_reference' => false,
                'multiple' => true,
                'expanded' => false,
            ]);
    }

In the department definition we explicitly ask to display the label field in our list, via the "choice_label" parameter.

This allows us to display a nicer label than just the id. But for this, we must add the following methods in the department entity.

//Permet d'afficher un nom plus sympa dans les messages du CRUD
    public function __toString(): ?string
    {
        return $this->id." : ".$this->nomClairRiche;
    }
//Permet d'afficher un label dans notre liste de configuration
    public function getLabel(): ?string
    {
        return $this->id." : ".$this->nomClairRiche;
    }

Adapt the example to the installed version

The Symfony and Sonata examples remain tied to the versions indicated in the article. Symfony 4.x and Symfony 6.2 are no longer maintained: for a current project, use a maintained branch and the documentation that exactly matches your dependencies.

php bin/console about
composer show symfony/framework-bundle sonata-project/admin-bundle

Before resuming the code, check the signatures, services, routes, and templates concerned. Then add a functional test covering permissions, HTTP code, and the visible result.

Reference: maintained Symfony versions.