Laravel Jensseger Mongodb includesToMany返回空数组 [英] Laravel Jensseger Mongodb belongsToMany returns empty array

问题描述

我正在尝试通过以下方式使用belongsToMany关系: 带有belongsToMany关系的模型:

I am trying to use a belongsToMany relation, in the following way: Model with belongsToMany relation:

namespace App\Models;
use Illuminate\Notifications\Notifiable;
use Laravel\Passport\HasApiTokens;
class Notification extends \Jenssegers\Mongodb\Eloquent\Model
{
    use Notifiable, HasApiTokens;
    protected $collection = 'myDb.notifications';
    protected $fillable = [ ];
    protected $hidden = [  ];

    /**
    * List of involved users
    */
    public function participants()
    {
      return $this->belongsToMany(User::class);
    }
}

创建模型:

$notification=new Notification();
....
$notification->participants()->attach(["5b13fb4393782d5e9010835d","5b13146f93782d29254c8cb2"]);
$notification->save();

赠予:

{
    ......
    "user_ids": [
        "5b13fb4393782d5e9010835d",
        "5b13146f93782d29254c8cb2"
    ],
    "updated_at": "2018-06-07 12:32:19",
    "created_at": "2018-06-07 12:32:19",
    "_id": "5b1925d393782d24b4514a16"
}

因此，当我尝试通过以下方式快速加载ID时，它们会正确附加:

So ids are attached correctly, however, when I try to eager-load them with:

Notification::where('_id','=','5b1925d393782d24b4514a16')->with(['participants'])->get()

我得到一个用于该关系的空数组:

I get an empty array for the relation:

[
    {
        "_id": "5b1925d393782d24b4514a16",
        ....
        "updated_at": "2018-06-07 12:32:19",
        "created_at": "2018-06-07 12:32:19",
        "participants": []
    }
]

我还使用以下方法验证了给定的用户确实存在，并且应该可加载":

I have also verified that the given users actually exist, and should be "loadable", using:

User::whereIn('_id',["5b13fb4393782d5e9010835d","5b13146f93782d29254c8cb2"])->get()

这给了两个用户预期的....

Which gives the two users as expected....

推荐答案

显然，我们需要双向关系，即我们都需要两个表中的ID.
我们还需要手动设置键(或者可能不是，但是我不确定什么是正确的约定)

Apparently we need two-way relationship, i.e. we need ids in BOTH tables.
We also need to set keys manually (or perhaps not, but I'm not sure what's right convention)

class Notification extends ...
{
    public function participants()
    {
      // NOTE: we set keys manually here:
      return $this->belongsToMany(User::class, null, 'notification_ids', 'user_ids');
    }
}

class User extends ...
{
    public function notifications()
    {
      // NOTE: we set keys manually here:
      return $this->belongsToMany(Notification::class, null, 'user_ids', 'notification_ids');
    }
}

考虑对象具有以下属性(字段):

Considering objects have following properties (fields):

用户:

{
   ...
   notification_ids: []
}

通知:

{
   ...
   user_ids: []
}

(两个字符串(id)的数组)

(both array of strings (ids))

使用附件应正确更新两个表，例如:

Using attach should update both tables properly, for example:

$user->notifications()->attach($notification->id)

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