Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"_id":1,"arr":["foo","bar"]}]
Query
db.collection.update({_id:1},[{$project:{arr:{$setUnion:["$arr",["baz","abc","bar"/**will not be duped*/]]}}}])
Result