Yii2 iterate dataprovider with relations - iterator

Question

I need to know how to iterate through a Yii2 dataprovider with relations.
I have a model Asset that has a relationship to another model Make.
class Equipment extends \yii\db\ActiveRecord
{
// ...
public function getMake() {
return $this->hasOne(Make::className(), ['make_id' => 'make_id']);
}
}
In my controller, I have 2 functions, one to render a grid, and another to export the data to a CSV file.
public function actionEquipment()
{
$searchModel = new EquipmentSearch();
$dataProvider = $searchModel->search(Yii::$app->request->queryParams);
// Store the search model in session
Yii::$app->session->set('exportEquipmentModel', $searchModel);;
// Render grid
return $this->render('equipment', [
'searchModel' => $searchModel,
'dataProvider' => $dataProvider,
]);
}
public function actionExportequipment()
{
header('Content-type: text/csv');
header('Content-Disposition: attachment; filename="equipment_report-' . date('YmdHi') .'.csv"');
$searchModel = new EquipmentSearch();
$dataProvider = $searchModel->search(Yii::$app->request->queryParams);
// Use the search model from session, or get all
if(\Yii::$app->session->get('exportEquipmentModel')) {
$searchModel = Yii::$app->session->get('exportEquipmentModel');
$dataProvider = $searchModel->search(false);
$dataProvider->setPagination(false);
}
// csv header
$columns =[
'serial_number',
'Make',
'Model',
];
echo implode(",", $columns) . " \r\n";
// csv data
foreach ($dataProvider->getModels() as $data) {
$row =[
$data['serial_number'],
// TODO: I need to resolve the relation here
$data['make_id'] // Works
// $data->make_id // Works
// $data->make->description // Does not work
// $data['make_id']['description'], // Does not work
$data['model_id']
];
echo implode(",", $row) . " \r\n";
}
}
As can be see from the comments in the code, various forms of getting the make->description field is not yielding results.

Answer 1

Lesson learned : Always check for errors.
My code was correct. However, the data was not what I expected. The dba deleted some of the makes and models after setting off foreign key checks. Therefore, $data->make.
I therefore changed the line
$data->make->description
to
!empty($data->make)?$data->make->description:'Not Set',