Ordered Results Set within a relationship using Laravel - php

Question

I have a table structure that has this structure:
User (has many) Subjects (has many) Modules (has many) Topics (has many) Notes
I have foreign keys in each table like so:
Subject (user_id), Modules(subject_id), Topics(module_id), Notes(topic_id)
I want to have a way to access all the notes created by a user ordered by the date created. Is this possible using the query builder?
Note.php
class Note extends Model implements SluggableInterface
{
use SluggableTrait;
protected $sluggable = [
'build_from' => ['question', 'id'],
'save_to' => 'slug'
];
protected $fillable = ['question', 'answer', 'topic_id'];
public function topic()
{
return $this->belongsTo('App\Topic');
}
}
Topic.php
class Topic extends Model implements SluggableInterface
{
use SluggableTrait;
protected $sluggable = [
'build_from' => ['title', 'id'],
'save_to' => 'slug'
];
protected $fillable = ['title', 'module_id'];
public function notes()
{
return $this->hasMany('App\Note');
}
public function module()
{
return $this->belongsTo('App\Module');
}
}

Answer 1

There are a few ways to do this. If you wish to use your relationships, you will need to nest a few loops to make your way through the entire "tree" of relationships.
$user = User::with('subjects.modules.topics.notes')->find($user_id);
$notes = new Illuminate\Database\Eloquent\Collection;
foreach($user->subjects as $subject) {
foreach($subject->modules as $module) {
foreach($module->topics as $topic) {
foreach($topic->notes as $note) {
$notes->add($note);
}
}
}
}
$notes = $notes->sortBy('created_at');
As for making it easier through database design, that's a tough question without knowing what the rest of your app is doing. If this is the only place where you have any notes, then I would say probably it's the ideal solution. If other places need notes too, then it might be a problem.
Another approach would have to been to use the query builder which wouldn't require you to loop through any result sets but would require you write the sql. I wouldn't say it's simpler or easier though.
$notes = \DB::table('users')
->select('notes.*')
->join('subjects', 'users.id', '=', 'subjects.user_id')
->join('modules', 'subjects.id', '=', 'modules.subject_id')
->join('topics', 'modules.id', '=', 'topics.module_id')
->join('notes', 'topics.id', '=', 'notes.topic_id')
->where('users.id', $user_id)
->get();

Answer 2

I am not 100% sure because of naming conventions:
$user = User::with(['subjects.modules.topics.notes' => function($query)
{
$query->orderBy('created_at')
}])->whereId($user_id)->first();
dd($user);
Give me feedback in comments what you get.