Laravel 8: Method IlluminateDatabaseEloquentCollection::update does not exist ERROR

I want to update some data from the DB, so I added this Controller method:

public function updateAnswer(Answer $anss)
    {
        $validate_data = Validator::make(request()->all(),[
           'answer' => 'required'
        ])->validated();

        $answer = Answer::findOrFail($anss);
        $answer->update($validate_data);
        return back();
    }

Now the problem is I get this error:

Method IlluminateDatabaseEloquentCollection::update does not exist.

So how to solve this issue?

Answer

You are already resolving $anss using route-model binding.

public function updateAnswer(Answer $anss)

You are trying to call findOrFail with a model as an argument, which since Model implements Arrayable will return a Collection, thus breaking the update call.

See IlluminateDatabaseEloquentBuilder findOrFail -> find -> findMany -> return $this->whereKey($ids)->get($columns);.

Try:

    public function updateAnswer(Answer $anss)
    {
        $validate_data = Validator::make(request()->all(),[
           'answer' => 'required'
        ])->validated();

        $anss->update($validate_data);

        return back();
    }