Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"_id":"1","name":"x","images":{"image":"y.jpg","_id":0.0222231654}}]
Query
db.collection.aggregate([{$set:{image:{"$concat":["http://","$name",".com/","$image"]}}}])
Result