Retrieving data from junction table via foreign key - Laravel - mysql

Question

I'm trying to get data from a junction table and display it, so I have a users table and my junction table prescription_user. Prescription_user table has a user_id and prescription_id.
So what I'm trying to do is on this userdetails page, show all of this users prescriptions and access the prescription name and description etc, however when I try any of this I get "Trying to get property of non-object"
The models are set up to eager load correctly I think, the user model has a hasMany relation with the prescription_user model, and the prescription_user model has a belongsTo the user model.
Controller
function viewUserDetails($userId)
{
$logged_user_id = Auth::user()->id;
$user = User::find($logged_user_id);
$prescriptions = Auth::user()->prescription_user;
$fullname = $user->firstname ." ". $user->surname;
$email = $user->email;
$address = $user->address;
$postcode = $user->postcode;
$dob = $user->dateofbirth;
$uniquepatientnumber = $user->uniquepatientnumber;
$data = [];
$data['fullname'] = $fullname;
$data['email'] = $email;
$data['address'] = $address;
$data['postcode'] = $postcode;
$data['dateofbirth'] = $dob;
$data['uniquenumber'] = $uniquepatientnumber;
$data['prescriptions'] = $prescriptions;
return view('user/userdetails')->withData($data);`
userdetails blade
#extends('layouts.master')
#section('title', 'My Details')
#section('content')
<h1>My Details </h1>
<ul>
<li>Name: {{ $data['fullname'] }}</li>
<li>Email: {{ $data['email'] }}</li>
<li>Address: {{ $data['address'] }}</li>
<li>Postcode: {{ $data['postcode'] }}</li>
<li>Date of Birth: {{ $data['dateofbirth'] }}</li>
<li>Your Unique number is: {{ $data['uniquenumber'] }}</li>
<li>Your are currently prescribed {{$data['prescriptions']}}</li>
<p>Note: If you believe any of these are incorrect please contact a receptionist</p>
</ul>
#endsection``

Answer 1

There are some design flaws in what you have explained. You have a User model and a Prescription model. That means prescription_user is your pivot table (not junction table). If so far I'm correct, it means User and Prescription have a Many to many relationship. To prove my point, you said
Prescription_user table has a user_id and prescription_id.
That means prescription_user is the pivot table.
In your user model, define a many to many relationship with prescription. And vice versa.
User model
public function prescriptions() {
return $this->belongsToMany(Prescription::class, 'prescription_user', 'user_id', 'prescription_id');
}
Then you can change your controller function like this
public function viewUserDetails()
{
$user = Auth::user();
$prescriptions = $user->prescriptions;
return view('user/userdetails', compact('user', 'prescriptions'));
}
And your view
#extends('layouts.master')
#section('title', 'My Details')
#section('content')
<h1>My Details </h1>
<ul>
<li>Name: {{ $user->firstname }} {{ $user->surname }}</li>
<li>Email: {{ $user->email }}</li>
<li>Address: {{ $user->address }}</li>
<li>Postcode: {{ $user->postcode }}</li>
<li>Date of Birth: {{ $user->dateofbirth }}</li>
<li>Your Unique number is: {{ $user->uniquepatientnumber }}</li>
</ul>
Your are currently prescribed
<ul>
#foreach($prescriptions as $prescription)
<li>{{ $prescription->name }}
#endforeach
</ul>
<p>Note: If you believe any of these are incorrect please contact a receptionist</p>
#endsection
Your code would be neater and working great
Update
Getting data from the pivot table is relatively simple. Define those columns in the relationship
public function prescriptions() {
return $this->belongsToMany(Prescription::class, 'prescription_user', 'user_id', 'prescription_id')->withPivot('column1', 'column2');
}
In your view, you display it like this
{{ $prescription->pivot->column1 }} {{ $prescription->pivot->column2 }}

Answer 2

First I'm not sure that withData() is a thing. Just ->with($data).
Second, there is some confusion at the beginning of your function. You pass in a $userId, that you never use. Then you get the id from Auth::user(), then get a user with that id, which you already had. So just $user = Auth::user();
Third, you only get that error trying to use the -> operator on a non-object, and you only use it on $user-> and Auth::user()->
Since you got the user from Auth::user in the first place, I'm guessing it failed right out of the box at Auth::user()->id, and there is no Auth::user, but you would have to post a little more data, either from the error in the browser or from storage/logs/laravel.log.
BUT, if I use this code
Route::get('/', function () {
$user = \Auth::user();
die($user->name);
return view('welcome');
}
where there clearly is no Auth::user() (I haven't even got to a login yet) I get this output:
ErrorException in web.php line 16:
Trying to get property of non-object
1. in web.php line 16
2. at HandleExceptions-> ... array('user'=>null)
So it's probaby that.