关于 Laravel 预加载问题请教

现有数据库
1、sale(id,stroe_id,name)
sale Mode 里面关联：

    public function store()
    {
        return $this->belongsTo(Store::class);
    }

2、stroe 字段（id,mdname）；

查询代码按照教程写的如下：

        $sales = Sale::limit(3)->get();
        foreach ($sales as $book) {
            echo $book->store->mdname;
        }

    $sales = Sale::limit(3)->with(['Store'])->get();
    foreach ($sales as $book) {
        echo $book->store->mdname;
    }

数据库查询日志：
[2018-10-01 15:19:53] local.INFO: select from sales limit 3
[2018-10-01 15:19:53] local.INFO: select from stores where stores.id = ? limit 1 ["153"]
[2018-10-01 15:19:53] local.INFO: select from stores where stores.id = ? limit 1 ["148"]
[2018-10-01 15:19:53] local.INFO: select from stores where stores.id = ? limit 1 ["166"]
[2018-10-01 15:19:53] local.INFO: select from sales limit 3
[2018-10-01 15:19:53] local.INFO: select from stores where stores.id in (?, ?, ?) ["148","153","166"]
[2018-10-01 15:19:53] local.INFO: select from stores where stores.id = ? limit 1 ["153"]
[2018-10-01 15:19:53] local.INFO: select from stores where stores.id = ? limit 1 ["148"]
[2018-10-01 15:19:53] local.INFO: select * from stores where stores.id = ? limit 1 ["166"]

并没有实现预加载 减少N+1 问题？求解