In learning the MongoDB platform, I'm at data models and see you can use embedding or references. My question is simple. Is there ever a need to use both? For example, I can see storing user contact data in an embedded document but perhaps storing transactions of the user (which could grow exponentially - think of your average high-rated eBay seller) in a reference model.
Was curious if its generally accepted that some applications will contain the blend. Wasn't very clear in the docs.
Thank you!