Yajra Relationship Call to undefined relationship [XXX_id] on model [App\XXX] - ajax

Question

I get an error like below
Call to undefined relationship [hotel_id] on model [App\Room]
Model file Hotel.php
class Hotel extends Model {
protected $primaryKey = 'id';
protected $fillable = ['hotel_name', 'hotel_area'];
public function room() {
return $this->hasMany('App\Room', 'hotel_id');
}
}
Model File Room.php
class Room extends Model {
protected $primaryKey = 'id';
protected $fillable = ['hotel_id', 'room_name', 'bonus_sum'];
public function hotel() {
return $this->belongsTo('App\Hotel', 'hotel_id');
}
}
Controller File RoomController.php
public function apiRoom() {
$rooms = Room::with('hotel');
return Datatables::eloquent($rooms)
->addColumn('action', function ($rooms) {
return '<a onclick="editForm('.$rooms->id.')" data-toggle="tooltip" data-original-title="Edit"> <i class="fa fa-pencil text-inverse m-r-10"></i> </a>'.
'<a onclick="deleteData('.$rooms->id.')" data-toggle="tooltip" data-original-title="Close"> <i class="fa fa-close text-danger"></i> </a>';
})
->escapeColumns()
->toJson();
Route file web.php
Route::get('rooms-list', 'RoomController#list');
Route::resource('room', 'RoomController', [
'except' => ['create']
]);
Route::get('api/room', 'RoomController#apiRoom')->name('api.room');
Migrate create_new_room
$table->increments('id');
$table->integer('hotel_id')->unsigned();
$table->foreign('hotel_id')->references('id')->on('hotels')->onDelete('cascade');
$table->string('room_name');
$table->string('bonus_sum');
$table->timestamps();
View File
$('#room-table').DataTable({
processing: true,
serverSide: true,
ajax: "{{ route('api.room') }}",
columns: [
{data: 'id', name: 'id'},
{data: 'hotel.hotel_name', name: 'hotel.hotel_name'},
{data: 'room_name', name: 'room_name'},
{data: 'bonus_sum', name: 'bonus_sum'},
{data: 'action', name: 'action', orderable: false, searchable: false}
]
});
It's not related to the database. There is probably an error in the ajax file.

Answer 1

Your hasMany has been defined incorrectly in your Hotel class.
Per the API documentation here, you need to pass an instance of the Room class through.
public function room() {
return $this->hasMany(App\Room::class, 'hotel_id');
// OR
return $this->hasMany('App\Room', 'hotel_id');
}
Same applies your Room class.
public function hotel() {
return $this->belongsTo(App\Hotel::class, 'hotel_id');
// OR
return $this->belongsTo('App\Hotel', 'hotel_id');
}
-- EDIT --
On the comment, the belongsTo function has the definition:
belongsTo($related, $foreignKey = null, $ownerKey = null, $relation = null)
For your hotel() relationship on the Room class to work, you need to pass the related models key as the second parameter. You should write it like this:
public function hotel() {
return $this->belongsTo('App\Hotel', 'id', 'hotel_id');
}