创建父级时创建模型（例如，在创建用户时创建5个帖子）

If a User has many posts, and a post belongs to user, it's simple to do:

$factory->define(App\Post::class, function ($faker) {
    return [
        'title' => $faker->title,
        'content' => $faker->paragraph,
        'user_id' => function () {

            // Creates a User for every Post
            return factory(App\User::class)->create()->id;
        }
    ];
});

How do I accomplish the opposite? Instead, creating say 5 posts when a user is created and associating that post to the newly created user?

~Edit I am using laravel 5.2, and I've declared my model relationships in my models, so I now have:

$user = factory(App\User::class)->create();
$posts = factory(App\Post::class, 3)->make();
$user->posts()->saveMany($posts);

// Great, now I have a User and 3 Posts associated with that user. 


// However, now, I want let's say, 5 votes per post.
// I can't call $posts->votes(), so I iterate

foreach ($posts as $post) { 
    $votes = factory(App\Votes::class, 5)->make();
    $post->votes()->saveMany($votes);
}

Then any other relation to votes, etc would just be nested in the foreach.

$factory->define(App\User::class, function ($faker) {
    return [
        'name' => $faker->name,
        'email' => $faker->email
    ];
});

$factory->define(App\Post::class, function ($faker) {
    return [
        'title' => $faker->title,
        'content' => $faker->paragraph
    ];
});


$user = factory(User::class)->create();

$post = factory(User::class)->create();

$user->posts()->associate($post);

Create 5 fakers in $posts

$posts = factory(App\Post::class, 3)->make();
$user->posts()->saveMany($posts);

I would use Model Events for that. In your AppServiceProvider, add the events as below:

namespace App\Providers;

use App\User;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        User::created(function ($user) {
            $posts = factory(App\Post::class, 3)->make();
            $user->posts()->saveMany($posts);
        });

        Post::created(function ($post){
            $votes = factory(App\Vote::class, 3)->make();
            $post->votes()->saveMany($votes);
        });
    }

Now you do not have to worry about the automatic creation, also, this should not be part of the Controller logic anyways.