hasOne(Order::className(), ['id' => 'order_id']); } public function getItem() { return $this->hasOne(Item::className(), ['id' => 'item_id']); } public static function getRecordSchema() { return new RecordSchema(array( 'name' => 'order_item', 'primaryKey' => ['order_id', 'item_id'], 'columns' => array( 'order_id' => 'integer', 'item_id' => 'integer', 'quantity' => 'integer', 'subtotal' => 'decimal', ) )); } }