Join performance in MongoDB 3.2 using $lookup

One of the key tenants of MongoDB schema design is to account for the absence of server-side joins.  Data is joined all the time inside of application code of course, but traditionally there’s been no way to perform joins within the server itself. 

This changed in 3.2 with the introduction of the $lookup operator within the aggregation framework.  $lookup performs the equivalent of a left outer join – eg: it retrieves matching data from another document and returns null data if no match is found.

Here’s an example using the MongoDB version of the Sakila dataset that I converted from MySQL back in this post: 

Please go to https://medium.com/dbkoda/coding-efficient-mongodb-joins-97fe0627751a to read the rest of this post (it has been migrated to a medium.com article and updated).