Laravel's Eloquent＆＃39; with＆＃39;数组正在破碎

Question

我正在尝试使用单个基类来抽象我的模型。我有三个继承自同一基础的模型：

1. 修复
2. 检验
3. 购买

我能够成功地将模型创建并保存到数据库，但是在获取时我得到一个空白屏幕，不会抛出任何错误。当我删除$with属性时，一切似乎都有效。

下面是代码：

abstract class ItemType extends Model 
{
    public    $timestamps = false;
    protected $with       = ['details'];

    public function details()
    {
         return $this->morphOne(Item::class, 'type', 'item_details_type', 'item_details_id', 'id');
    }
}

class Repair extends ItemType
{
    protected $table      = 'repairs';
    protected $guarded    = ['id', 'created_at', 'updated_at'];
    protected $morphClass = self::class;
}
class Inspection extends ItemType {}
class Purchase   extends ItemType {}

Answer 1

最后，我决定使用if segue.identifier == "newRecord" { let controller = (segue.destinationViewController as! NewRecordVC) let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate // instantiate the delegate methods in AppDelegate controller.managedContext = appDelegate!.managedObjectContext // create context from delegate methods let recordEntity = NSEntityDescription.entityForName("RecordData", inManagedObjectContext: controller.managedContext) let locationEntity = NSEntityDescription.entityForName("Location", inManagedObjectContext: controller.managedContext) controller.location = Location(entity: locationEntity!, insertIntoManagedObjectContext: controller.managedContext) controller.record = Record(entity: recordEntity!, insertIntoManagedObjectContext: controller.managedContext) print("segueing") } 关系而不使用抽象类来解决问题。