How to update only one property in MongoDB?

To update only one property in MongoDB, use the $set operator to modify a specific field without affecting other properties of the document. For arrays, use $addToSet or $push operators.

Syntax

db.collection.updateOne(
    { "field": "value" },
    { $set: { "propertyToUpdate": "newValue" } }
);

Sample Data

db.demo336.insertMany([
    { "Name": "Chris", "Score": [45, 67, 78] },
    { "Name": "David", "Score": [89, 93, 47] }
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5e522cb1f8647eb59e562097"),
        ObjectId("5e522cb2f8647eb59e562098")
    ]
}

Example 1: Update Single Property with $set

Update David's name to "David Smith" ?

db.demo336.updateOne(
    { "Name": "David" },
    { $set: { "Name": "David Smith" } }
);

{ "acknowledged": true, "matchedCount": 1, "modifiedCount": 1 }

Example 2: Add Values to Array Property

Add individual scores to David's Score array using $addToSet ?

db.demo336.updateOne(
    { "Name": "David" },
    { $addToSet: { "Score": { $each: [56, 34, 71] } } }
);

{ "acknowledged": true, "matchedCount": 1, "modifiedCount": 1 }

Verify Results

Display all documents to see the updates ?

db.demo336.find();

{ "_id": ObjectId("5e522cb1f8647eb59e562097"), "Name": "Chris", "Score": [45, 67, 78] }
{ "_id": ObjectId("5e522cb2f8647eb59e562098"), "Name": "David Smith", "Score": [89, 93, 47, 56, 34, 71] }

Key Points

• $set updates specific properties without affecting other fields
• $addToSet with $each adds multiple unique values to arrays
• Use updateOne() for single document updates

Conclusion

Use $set to update individual properties and $addToSet with $each for array modifications. These operators ensure only the target property is modified while preserving other document fields.