Template
single collection
multiple collections
mgodatagen
update
indexe
explain
Stage
Database
bson
mgodatagen
[{"array":[{name:1},{name:2},{name:3}]},]
Query
db.collection.update({},[{$set:{notes:{$concatArrays:[{$slice:["$array",1,]},{$slice:["$array",2,{$size:"$array"}]}]}}},])
Result