Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"_id":1,"rating":4.1}]
Query
db.collection.update({"_id":1},[{"$set":{"rating":{"$divide":[{"$sum":["$rating",5]},2]},"numOfRatings":{"$sum":["$numOfRatings",1]}}}])
Result