Invalid argument supplied for foreach() in laravel 5.3 - php

Question

I do not know exactly how this works, so that's why I'm asking. I'm still working on a Bulletin Board System and now I want under each category, a subcategory.
For example:
I have done this using the following thread on LaraCasts:
https://laracasts.com/discuss/channels/eloquent/eloquent-getting-subcategories-from-the-categories
Now my IndexController looks like this:
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Thread;
use App\Chat;
use App\Category;
class IndexController extends Controller
{
/**
* Show the application dashboard.
*
* #return \Illuminate\Http\Response
*/
public function index()
{
$threads = Thread::all()->toArray();
$chats = Chat::orderBy('id', 'DESC')->take(50)->with('author')->get();
$categories = Category::with('sub_category')->get();
return view('index', compact('threads','chats','categories'));
}
}
This is my Category Model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Category extends Model
{
public function sub_category()
{
return $this->belongsTo(self::class, 'parent_id', 'id');
}
public function parent_category()
{
return $this->hasMany(self::class, 'id', 'parent_id');
}
}
My view (index.blade.php):
#foreach($categories as $category)
<div class="col-md-8">
<div class="panel panel-primary">
<div class="panel-heading"><i class="fa fa-angle-right" aria-hidden="true"></i> {{ $category->caption }}</div>
<div class="panel-body">
#foreach($category->sub_category as $sub_category)
<div class="row forum-row">
<div class="col-xs-12 col-md-8 col-sm-8">
<div class="hidden-xs visible-sm visible-lg visible-md pull-left forum-icon-read">
<i class="fa fa-comment"></i>
</div>
{{ $sub_category->caption }}<br>
<small>{{ $sub_category->desc }}</small>
</div>
<div class="col-xs-12 col-md-4 col-sm-4 forum-latest-container">
<p class="forum-data cutoff">Test</p>
<small>
door <a class="Donateur" href="/user-Sygun">Sygun</a>
<p class="forum-data">
2 minuten geleden </p>
</small>
</div>
</div>
#endforeach
</div>
</div>
</div>
#endforeach
I also have two database tables:
Sub_categories (id, caption, parent_id, min_rank, desc)
Categories (id, caption, min_rank, desc)
The error message I get:
Invalid argument supplied for foreach()
Can you tell me what is the right way to achieve this?

Answer 1

Create two model named Category and SubCategory.
In Category model
public function subcategories()
{
return $this->hasMany('App\SubCategory', 'parent_id');
}
In SubCategory model
public function parent_category()
{
return $this->belongsTo('App\Category', 'parent_id');
}
Then in your controller query it like:
$categories = Category::with('subcategories')->get();
And hopefully your foreach will work.

Answer 2

Category model
public function subcategories(){
return $this->hasMany('SubCategory', 'parent_id');
}
On view
#foreach($categories as $category)
#foreach($category->subcategories as $subcategory)
{{$subcategory->caption}}
#endforeach
#endforeach
And make sure you create SubCategory model.