属于父模型的三个模型的Laravel 8关系

class ParentModel extends Model
{
    public function modelAs()
    {
        return $this->hasMany(ModelA::class);
    }

    public function modelBs()
    {
        return $this->hasMany(ModelB::class);
    }

    public function modelCs()
    {
        return $this->hasMany(ModelC::class);
    }
}

class ModelA extends Model
{
    public function parentModel()
    {
        return $this->belongsTo(ParentModel::class);
    }
}

class ModelB extends Model
{
    public function parentModel()
    {
        return $this->belongsTo(ParentModel::class);
    }
}

class ModelC extends Model
{
    public function parentModel()
    {
        return $this->belongsTo(ParentModel::class);
    }
}

Schema::create('model_a', function (Blueprint $table) {
    $table->id();
    $table->unsignedBigInteger('parent_model_id');
    $table->string('name');
    $table->timestamps();

    $table->foreign('parent_model_id')->references('id')->on('parent_models')->onDelete('cascade');
});

$parentModel = ParentModel::find(1);

$allModelAs = $parentModel->modelAs;
$allModelBs = $parentModel->modelBs;
$allModelCs = $parentModel->modelCs;

$parentModel = ParentModel::find(1);

$modelA = new ModelA(['name' => 'Example A']);
$parentModel->modelAs()->save($modelA);

$modelB = new ModelB(['name' => 'Example B']);
$parentModel->modelBs()->save($modelB);

$modelC = new ModelC(['name' => 'Example C']);
$parentModel->modelCs()->save($modelC);