Laravel Eloquent: Multiple Foreign Keys from One Primary Key - laravel

Question

I am in-progress to create a project in Laravel.
I have two Database Table, which is created by migrations:
I want to setup multiple foreign key in database schema.
Table User
Schema::create('tr_users', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('email');
$table->timestamp('email_verified_at')->nullable();
$table->rememberToken();
$table->string('password');
$table->unsignedBigInteger('departement_id')->nullable();
$table->foreign('departement_id')
->references('id_departement')->on('tr_departements')
->onUpdate('cascade')
->onDelete('cascade');
});
Table Departrements
Schema::create('tr_departements', function (Blueprint $table) {
$table->bigIncrements('id_departement');
$table->string('name');
$table->timestamps();
$table->unsignedBigInteger('created_by')->nullable();
$table->foreign('created_by')
->references('id')->on('tr_users')
->onDelete('cascade');
$table->unsignedBigInteger('updated_by')->nullable();
$table->foreign('updated_by')
->references('id')->on('tr_users')
->onDelete('cascade');
});
What I want to know is how to describe relation in Models?
Edit:
My plan to use this relation is every users is belongs to departement, and any departement has many users, and every users has only one departement

Answer 1

If you are seeking One-to-One relationship from user to department then relation would be like this:
In your User model code would be like this:
public function department()
{
return $this->hasOne('App\Department');
}
And in your department model:
public function user()
{
return $this->belongsTo('App\User');
}
For multiple relationship you can refer laravel documentation