Laravel 8 - Eloquent Relationship cannot access relation properties / values

Question

Model 1: Walks

       return $this->belongsTo('App\Models\Device','device_uuid','device_uuid');
   }

Model 2: Device

  public function walks() {
        return $this->hasMany('App\Models\Walks','device_uuid','device_uuid');
    }

In my index file:

     <table class="table table-bordered">
            <tr>
                <th>No</th>
                <th>Walk Date</th>
                <th>Device Name</th>
                <th>In</th>
                <th>Out</th>
                <th width="280px">Action</th>
            </tr>
            @foreach ($walks as $walk)

            <tr>
                    <td>{{ ++$i }}</td>
                    <td>{{ $walk->walk_datetime }}</td>
                    <td>{{ $walk->device->device_uuid }}</td> <========
                    <td>{{ $walk->walk_in }}</td>
                    <td>{{ $walk->walk_out }}</td>
                    <td>
                        <form action="{{ route('walks.destroy',$walk->id) }}" method="POST">

                            <a class="btn btn-primary" href="{{ route('walks.edit',$walk->id) }}">Edit</a>

                            @csrf
                            @method('DELETE')
                            <button type="submit" class="btn btn-danger">Delete</button>
                        </form>
                    </td>
                </tr>
            @endforeach
        </table>

this causes errors:

<td>{{ $walk->device->device_uuid }}</td> <========

"Trying to get property 'device_uuid' of non-object"

If I do this:

<td>{{ $walk->device }}</td>

I get:

{"id":1,"device_uuid":"1902101300368","device_name":"Test 1","created_at":null,"updated_at":null}

which means the relation works correct.

Is there any other way that I should use to access the "device_mame" attribute?

Related to questions below.. All walks has a valid device linked.

1. walks list. This is what shows if I print -> $walk->device

2. walk list (DB)

3. devices list (DB)

Answer 1

:) It seems to me that some Walks don't have a Device. That's why it (usually) throws that error.

Similar problem on Laracasts.

Or what you can do is use ternary operators

<td>{{(isset($walk->device->device_uuid)? $walk->device->device_uuid : ''}}</td>