如何在Laravel Backpack中处理假的1-n关系？

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class ParentModel extends Model
{
    protected $appends = ['child'];

    public function getChildAttribute()
    {
        // 在这里编写获取子模型的逻辑
        return ChildModel::where('parent_id', $this->id)->get();
    }
}

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class ChildModel extends Model
{
    public function parent()
    {
        return $this->belongsTo(ParentModel::class, 'parent_id');
    }
}

$this->crud->addColumn([
    'name' => 'child',
    'label' => 'Child Models',
    'type' => 'select_multiple',
    'entity' => 'child',
    'attribute' => 'name',
    'model' => "App\Models\ChildModel",
]);