Error when trying to make relation in laravel - laravel

Question

I'm trying to make a relationship in Laravel but always get the error:
Trying to get property 'nama_guru' of non-object (View: D:\xampp\htdocs\supervisi_digital\resources\views\ManagementSupervisi\index.blade.php).
Here is my code:
Dokumen Model
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Dokumen extends Model
{
protected $table = "dokumen";
protected $primarikey = "id";
protected $fillable =
[
'id', 'nama_guru', 'mapel', 'file', 'keterangan'
];
public function supervisi()
{
return $this->hasMany(Supervisi::class);
}
}
Supervisi Model
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Supervisi extends Model
{
protected $table = "supervisi";
protected $primarikey = "id";
protected $fillable =
[
'id', 'id_guru', 'id_mapel', 'id_keterangan', 'penilaian'
];
public function dokumen()
{
return $this->belongsTo(Dokumen::class);
}
}
Blade View
<table>
<thead>
<tr>
<th>#</th>
<th>NAMA GURU</th>
<th>MAPEL</th>
<th>KETERANGAN</th>
<th>PENILAIAN</th>
<th>ACTION</th>
</tr>
</thead>
<tbody>
#foreach ($dtSupervisi as $item)
<tr>
<td>{{ $loop->iteration }}</td>
<td>{{ $item->dokumen->nama_guru }}</td>
<td></td>
<td></td>
<td></td>
</td>
</tr>
#endforeach
</tbody>
</table>
Controller
public function index()
{
$dtSupervisi = Supervisi::with('dokumen')->paginate(10);
return view('ManagementSupervisi.index', compact('dtSupervisi'));
}
I don't know what the problem is.

Answer 1

You need to define the foreign key and local key in your relationship.
public function dokumen()
{
return $this->belongsTo(Dokumen::class,'foreign_key','localkey');
}
so
public function dokumen()
{
return $this->belongsTo(Dokumen::class,'id_guru','id');
}

Answer 2

protected $fillable =
[
'id', 'id_guru', 'id_mapel', 'id_keterangan', 'penilaian', 'dokumen_id'
];
Use dokumen_id in Supervisi model and supervisi table after migrate database may be it's work