laravel eloquent inverse with code example

Example 1: associate laravel

When updating a belongsTo relationship, you may use the associate method. This 
method will set the foreign key on the child model:

	$account = App\Account::find(10);
	$user->account()->associate($account);
	$user->save();

When removing a belongsTo relationship, you may use the dissociate method. This
method will set the relationship foreign key to null:

	$user->account()->dissociate();
	$user->save();

Example 2: laravel how to query belongsTo relationship

$movies = Movie::whereHas('director', function($q) {
    $q->where('name', 'great');
})->get();