PianoTime/app/Models/Remark.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Remark extends Model
{
    protected $table = 'remarks';

    protected $guarded = [];

    public function teacher()
    {
        return $this->belongsTo('App\Models\Teacher');
    }

    public function student()
    {
        return $this->belongsTo('App\Models\Student');
    }

    public function course()
    {
        return $this->belongsTo('App\Models\Course');
    }
}