Can't get data just saved in database in Laravel 5.1

I successfully save data in the database. However, the data can't be found after saving.

In the JSON，the key object's value is an empty array. My object model:

protected $table = 'objects';
public $timestamps = false;
protected $primaryKey = 'object_id';
public $incrementing = false;
protected $fillable = ['object_id','object_lt_x', 'object_lt_y', 'object_width', 'object_height', 'image_id', 'type_id'];

Save the data to database

$obj = new Object;
$obj->object_id = $objectId;
$obj->object_lt_x = $objX;
$obj->object_lt_y = $objY;
$obj->object_width = $objWidth;
$obj->object_height = $objHeight;
$obj->image_id = $imageId;
$obj->type_id = $typeId;
if ($obj->save()) {
    $obj_id = $obj->object_id;
    $object = DB::table('objects')->where('object_id',$objectId)->get();
    $success = array('status' => 1,'message' => $type_name.'标记成功！','obj_id' => $obj_id,'object' => $object);
    return response()->json($success);
} else {
    $error = array('status' => 0,'message' => $type_name.'标记失败！');
    return response()->json($error);
}

The result is:

Object {status: 1, message: "眼睛标记成功！", obj_id: "A7313004-3B7D-56F2-602F-FC81D4A8F04F", object: Array[0]}

via Chebli Mohamed