Auto-update denormalized attributes with MongoDb and Yii2

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where the ```address_id``` field is a foreign id to:

```tbl_address```

- id: ```int(11)``` 
 
 
- street: ```varchar(255)```

- city_id: ```int(11)```

where the ```city_id``` field is a foreign key to the ```tbl_city``` etc...
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