Update injected model from route in Laravel - php

Question

I am trying to update some values and it's creating a new one instead of updating the selected data
this is the controller code
public function update(Request $request, Payment_Student $payment_Student)
{
$payment_Student->date =request('date');
$payment_Student->amount =request('amount');
$payment_Student->formation_id =request('formation_id');
$payment_Student->student_id =request('student_id');
$payment_Student->save();
return redirect()->route('payment.index');
}
This is my route code
Route::get('/home', 'HomeController#index')->name('home');
Route::get('/search','CategoryController#search');
Route::resource('/category','CategoryController');
Route::resource('/formation','FormationController');
Route::resource('/professor','ProfessorController');
Route::resource('/student','StudentController');
Route::resource('/classroom','ClassroomController');
Route::resource('/session','SessionController');
Route::resource('/payment','PaymentController');
Route::resource('/seance','SeanceController');
Route::resource('/paymentprof','PaymentProfessorController');
Route::resource('/paymentstudent','PaymentStudentController');
Route::resource('/presence','PresenceController');
Route::resource('/profile','ProfileController');
This is my balde view code
<form method="POST" enctype="multipart/form-data" action="{{route('paymentstudent.update',$payment_Student->id)}}" class="form-horizontal">
{{method_field('PATCH')}}
#csrf
Date:
<br/>
<input class="form-control" type="date" name="date">
<br/>
Amount:
<input type="number" value="{{$payment_Student->amount}}" name="amount"
class="form-control">
<br/>
Formation:
<select class="form-control" name="formation_id">
#foreach($formation as $formation)
<option value="{{$formation->id}}">{{$formation->name}}</option>
#endforeach
</select>
<br/>
Student:
<select class="form-control" name="student_id">
#foreach($student as $student)
<option value="{{$student->id}}">{{$student->lastname}}</option>
#endforeach
</select>
<div class="card-footer">
<button type="submit" class="btn btn-primary">Save Changes</button>
</div>
<br>
</form>
when I select a data to update it creates new data the updated value that I have inserted

Answer 1

By default when you make a resource laravel will singularize the resource name and make a variable out of it.
Example: Route::resource('videos', 'VideoController') laravel will expect the variable $video
In your case, paymentstudent will probably give the variable $paymentstudent
Fortunatly, you can customize your own parameter name
Route::resource('paymentstudent', 'PaymentStudentController', ['parameters' => [
'paymentstudent' => 'payment_Student'
]]);

Answer 2

Fetch the eloquent model from the one passed in the route and update accordingly, since you're using route resource, pass the actual object in the route by named parameter
<form method="POST" enctype="multipart/form-data" action="{{ route('paymentstudent.update', ['paymentstudent' => $payment_Student]) }}"
public function update(Payment_Student $payment_Student)
{
$payment_Student = Payment_Student::find($payment_Student->id);
$payment_Student->date = request('date');
$payment_Student->amount = request('amount');
$payment_Student->formation_id = request('formation_id');
$payment_Student->student_id = request('student_id');
$payment_Student->save();
return redirect()->route('payment.index');
}