Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{existingField1:"(b)",existingField2:"(d)"}]
Query
db.collection.update({},[{$set:{newField:{$concat:["some_extra_string","$existingField1","other_extra_string","$existingField2"]}}}])
Result