MongoDB query to update selected fields

To update selected fields in MongoDB, use the update() method with the $set operator. The $set operator modifies specific fields without affecting other document properties.

Syntax

db.collection.update(
    { "field": "matchValue" },
    { $set: { "field": "newValue" } }
);

Create Sample Data

Let us create a collection with sample documents ?

db.demo352.insertMany([
    { "Name": "Chris" },
    { "Name": "David" },
    { "Name": "Bob" },
    { "Name": "Mike" }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e55510af8647eb59e5620ba"),
        ObjectId("5e55510ef8647eb59e5620bb"),
        ObjectId("5e555112f8647eb59e5620bc"),
        ObjectId("5e555115f8647eb59e5620bd")
    ]
}

Display all documents from the collection ?

db.demo352.find();

{ "_id": ObjectId("5e55510af8647eb59e5620ba"), "Name": "Chris" }
{ "_id": ObjectId("5e55510ef8647eb59e5620bb"), "Name": "David" }
{ "_id": ObjectId("5e555112f8647eb59e5620bc"), "Name": "Bob" }
{ "_id": ObjectId("5e555115f8647eb59e5620bd"), "Name": "Mike" }

Example: Update Selected Field

Update David's name to Robert using $set ?

db.demo352.update(
    { "Name": "David" },
    { $set: { "Name": "Robert" } }
);

WriteResult({ "nMatched": 1, "nUpserted": 0, "nModified": 1 })

Verify Result

Display all documents to verify the update ?

db.demo352.find();

{ "_id": ObjectId("5e55510af8647eb59e5620ba"), "Name": "Chris" }
{ "_id": ObjectId("5e55510ef8647eb59e5620bb"), "Name": "Robert" }
{ "_id": ObjectId("5e555112f8647eb59e5620bc"), "Name": "Bob" }
{ "_id": ObjectId("5e555115f8647eb59e5620bd"), "Name": "Mike" }

Conclusion

The $set operator allows you to update specific fields in MongoDB documents while preserving other existing fields. Use it with update() to modify only the fields you need to change.