How to update array of objects to LowerCase in mongodb? - mongodb

Question

I need to update the role in team array to lowercase.
db.users.find().pretty().limit(1)
{
"_id" : ObjectId("5d9fd81d3d598088d2ea5dc9"),
"employed" : "USA-Atlanta",
"firstName" : "Rory",
"siteRole" : "super admin",
"status" : "active",
"team" : [
{
"name" : "SALES AND MARKETING",
"displayName" : "S&M",
"role" : "Manager"
}
]
}
Tried this code.I m getting it with normal fields.
db.users.find( {}, { 'role': 1 } ).forEach(function(doc) {
db.users.update(
{ _id: doc._id},
{ $set : { 'role' : doc.role.toLowerCase() } },
{ multi: true }
)
});
sample output
"team" : [
{
"name" : "SALES AND MARKETING",
"displayName" : "S&M",
"role" : "manager"
}
]

Answer 1

I think the below Aggregation query is what you are looking for
var count = 0;
db.users.aggregate([
{
"$match": {
"team.role": {$exists: true}
}
},
{
"$project": {
"_id": 1,
// "team": 1,
"teamModified": {
"$map": {
"input": "$team",
"as": "arrayElems",
"in": {
"$mergeObjects": [
"$$arrayElems",
{"role": {"$toLower": "$$arrayElems.role"}}
]
}
}
}
}
},
]).forEach(function(it) {
db.users.updateOne({
"_id": it["_id"]
}, {
"$set": {
"team": it["teamModified"]
}
})
printjson(++count);
})
printjson("DONE!!!")
Note: I haven't tested the script properly in my local, so do let me know if it didn't help you out