PHP

Yii2 Dynamic Relational, Lazy loading

// SELECT * FROM `customer` LIMIT 100
$customers = Customer::find()->limit(100)->all();

foreach ($customers as $customer) {
    // SELECT * FROM `order` WHERE `customer_id` = ...
    $orders = $customer->orders;
}

Yii2 Dynamic Relational, Eager loading

// SELECT * FROM `customer` LIMIT 100;
// SELECT * FROM `orders` WHERE `customer_id` IN (...)
$customers = Customer::find()
    ->with('orders')
    ->limit(100)
    ->all();

foreach ($customers as $customer) {
    // no SQL executed
    $orders = $customer->orders;
}