php Laravel“未定义的方法Illuminate\Database\Query\Builder::attach()”

Laravel "undefined method Illuminate\Database\Query\Builder::attach()"

提问by glasstree

I'm trying to associate related models during database seeding in Laravel 4. According to the documentation here, I can do it like this:

我正在尝试在 Laravel 4 中的数据库播种期间关联相关模型。根据此处的文档，我可以这样做：

$user->roles()->attach(1);

So, in my database seed I'm running:

所以，在我的数据库种子中，我正在运行：

$package = Package::create([
    'name' => $faker->word,
    'summary' => $faker->sentence,
    'base_price' => $faker->randomFloat(2, 200, 10000)
]);

// Attach 1-5 randomly selected items to this package
foreach(range(1, 5) as $index)
{
    $randomItem = Item::orderBy(DB::raw('RAND()'))->first();
    $package->items()->attach($randomItem->id);
}

The packages items have already been seeded at this point, and they seed without problems. The above code gives this from Artisan though:

包裹项目此时已经播种，它们播种没有问题。上面的代码虽然从 Artisan 给出了这个：

[BadMethodCallException]                                              
Call to undefined method Illuminate\Database\Query\Builder::attach()

Someone hereseems to think that the attach()method doesn't actually exist and the docs are wrong, but I find that hard to believe.

这里有人似乎认为该attach()方法实际上并不存在并且文档是错误的，但我发现这很难相信。

TL;DR What is the correct way to create many-to-many relationships in Eloquent?

TL;DR 在 Eloquent 中创建多对多关系的正确方法是什么？

回答by TonyArra

The function items()in your Packagemodel has to return a BelongsToManyrelationship in order to use attach().

该功能items()在你的包模型必须返回一个BelongsToMany为了关系到使用的attach（） 。

public function items() {
  return $this->belongsToMany('Item');
}