[PHP][Laravel] 无法使用 Laravel Eloquent ORM 从另一个表中显示/获取列

Question

im trying to show or get column from another table using eloquent laravel, but it seems i have miss something or typo. Im using Laravel 9, and i've followed all the instructions video and documentation and all of them seems to be not working.

Error message says: Attempt to read property "deskripsi" on null

Migrations:

• table bisnis:

 public function up() { Schema::create('t_bisnis', function (Blueprint $table) { $table->id(); $table->string('deskripsi', 255); $table->string('pemilik', 255); $table->timestamps(); }); } /** * Reverse the migrations. * * @return void */ public function down() { Schema::dropIfExists('t_bisnis'); }

• table group:

 public function up() { Schema::create('t_grup_layanan', function (Blueprint $table) { $table->id(); $table->foreignId('bisnis_id')->nullable()->index('fk_bisnis_to_grup'); $table->string('deskripsi', 255); $table->timestamps(); }); } /** * Reverse the migrations. * * @return void */ public function down() { Schema::dropIfExists('t_grup_layanan'); }

Models:

• bisnis:

 class Business extends Model { use HasFactory; protected $table = 't_bisnis'; protected $guarded = []; protected $primary_key = 'id'; protected $with = ['group']; protected $fillable = [ 'deskripsi', 'pemilik' ]; public function group(){ return $this->hasOne(GroupService::class); } }

• group:

 class GroupService extends Model { use HasFactory; protected $table = 't_grup_layanan'; protected $guarded = []; protected $primary_key = ''; protected $fillable = [ 'bisnis_id', 'deskripsi' ]; protected $with = []; public function service(){ return $this->hasMany(Service::class); } public function business() { return $this->belongsTo(Business::class); } }

My blade:

 @foreach ($list as $item) <tr> <td>{{ $loop->iteration }}</td> <td>{{ $item->id }}</td> <td>{{ $item->business->deskripsi }}</td> <td>{{ $item->deskripsi }}</td> <td>{{ $item->updated_at->diffForHumans() }}</td> <td> {{-- <a href="#" class="badge bg-success"><span data-feather="eye"></span></a> --}} <a href="{{ route('gruplayanan.edit', $item->id) }}" class="badge bg-warning"><span data-feather="edit"></span></a> <form action="{{ route('gruplayanan.delete', $item->id) }}" method="post" class="d-inline"> @method('delete') @csrf <button class="badge bg-danger border-0" onclick="return confirm('Are you sure?')"><span data-feather="x-circle"></span></button> </form> </td> </tr> @endforeach

My controller:

 class GroupServiceController extends Controller { /** * Display a listing of the resource. * * @return \Illuminate\Http\Response */ public function index() { $list = GroupService::all(); return view('dashboard.gruplayanan.main', compact('list')); }

Answer 1

When you create a belongsTo relation in a model it automatically assumes that the relation key is {the name of the function}_id .

In your case it looks for a business_id field in the t_grup_layanan table, because your function name is business.

You can override this behavior by giving a second parametor to the belongs to function which is the foreign key name.

public function business()
{
    return $this->belongsTo(Business::class, 'bisnis_id');
}

This should do the trick.

You can find information about this in the official documentation if you scroll down just a little here