yii2里的hasOne怎么搞？

​​hasOne​​一对多关系，比如是吧。一个人有很多文章.

第二步：user:gii自动生成

models:

<?php
namespace frontend\models;
use yii\db\ActiveRecord;
use frontend\models\User;
class Article extends ActiveRecord
{
  public function getUserinfo()
  {
    return $this->hasOne(User::className(),['aid'=>'id']);
  }
}

控制器：

<?php
namespace frontend\controllers;
use frontend\models\Article;
use frontend\models\User;
class IndexController extends \yii\web\Controller
{

  public function actionIndex()
  {
    $article=Article::findOne(['id'=>2]);
    var_dump($article->userinfo);
}}