Applications get great efficiency from MongoDB by combining data that is accessed together into a single document. There are however situations where it is more efficient to have references between documents rather than embedding everything into a single document. This led to joins being our most requested feature. MongoDB 3.2 addresses this through the introduction of the $lookup stage in the aggregation pipeline to implement left-outer joins.
This webinar looks at $lookup as well as the other significant aggregation enhancements coming with MongoDB 3.2—why they're needed, what they deliver, and how to use them.
Want to learn more about what's new in MongoDB 3.2? Download the guide