Call to a member function update() on null [LARAVEL] - php

Question

I am trying to make a Laravel application that allows a logged-in user to edit one of their memorial pages. The edit view works, but as soon as the changes are saved, it throws a Call to a member function update() on null error. I am new to Laravel, so I apologize if this is a stupid question.
Controller:
public function edit(Memorial $memorial)
{
$this->authorize('update', $memorial);
return view('memorials.edit', compact('memorial'));
}
public function update(Memorial $memorial)
{
$this->authorize('update', $memorial);
$data = request()->validate([
'fname' => 'required',
'lname' => 'required',
'bio' => '',
]);
auth()->user()->memorial->update($data);
return redirect("/memorial/{$memorial->id}");
}
View:
<div class="container pt-5">
<form action="/memorial/{{ $memorial->id }}" enctype="multipart/form-data" method="POST">
<legend>Edit Memorial</legend>
#csrf
#method('PATCH')
<div class="form-group">
<div class="form-row">
<div class="col-6">
<input id="fname" type="text" class="form-control #error('fname') is-invalid #enderror" name="fname" placeholder="First Name" value="{{ old('fname') ?? $memorial->fname }}" autofocus>
#error('fname')
<span class="invalid-feedback" role="alert">
<strong>{{ $message }}</strong>
</span>
#enderror
</div>
<div class="col-6">
<input id="lname" type="text" class="form-control #error('lname') is-invalid #enderror" name="lname" placeholder="Last Name" value="{{ old('lname') ?? $memorial->lname }}">
#error('lname')
<span class="invalid-feedback" role="alert">
<strong>{{ $message }}</strong>
</span>
#enderror
</div>
</div>
</div>
<div class="form-group">
<div class="form-row">
<div class="col-6">
<input id="bio" type="text" class="form-control #error('bio') is-invalid #enderror" name="bio" placeholder="Biography" value="{{ old('bio') ?? $memorial->bio }}">
#error('bio')
<span class="invalid-feedback" role="alert">
<strong>{{ $message }}</strong>
</span>
#enderror
</div>
</div>
</div>
<div class="form-group">
<div class="form-row">
<div class="col-12">
<button class="btn btn-primary">Save</button>
</div>
</div>
</div>
</form>
Policy:
/**
* Determine whether the user can update the memorial.
*
* #param \App\User $user
* #param \App\Memorial $memorial
* #return mixed
*/
public function update(User $user, Memorial $memorial)
{
return $user->id == $memorial->user_id;
}

Answer 1

There are a few things that may be causing this error. I think the first place to investigate is on your relationship vs. what you are trying to update.
Your User model has many memorials:
public function memorials(){
return $this->hasMany(Memorial::class);
}
Your controller is trying to update one memorial:
auth()->user()->memorial->update($data);
To fix, I suggest you try to directly update the memorial in question, rather than through the user relationship. I assume there is a user_id key on the memorial - just add that in as you update the memorial that you have already injected into the update method.

Answer 2

Your relation is incorrect...You don't have memorial relation in User model. So it returns null
You can easily edit one memorial as below code:
public function update(Memorial $memorial)
{
$this->authorize('update', $memorial);
$data = request()->validate([
'fname' => 'required',
'lname' => 'required',
'bio' => '',
]);
$memorial->update($data);
return redirect("/memorial/{$memorial->id}");
}
because in authorize you check the privacy when you edit $memorial that is what you need

Answer 3

so I see the reason is:
in User model you define the memory relation:
public function memorials()
{
return $this->hasMany(Memorial::class);
}
in function update() you call:
auth()->user()->memorial->update($data);
you are calling a model, and it has proposed to get property of Memorial model.
you need to call like this:
in function update():
auth()->user()->memorials()->update($data)
in User model
/**
* Eloquent：User
*
* //relation
* #property Collection|Memorial[] $memorials
*/
class User extends Model

Answer 4

Provided you've set your relationships correctly
Means that your had no memorial at all, i.e no memorial record which linked to that user_id, so nothing to update, thats what we say that relationship is null means its not existing.
You would never know if user have a relationship to memorial record or not so the trick is to create it if its not existing, or updating it if it exists with below simple eloquent code
auth()->user()->memorial->updateOrCreate($data);