Update multiple elements in an array in MongoDB?

To update multiple elements in an array in MongoDB, use the $[] all positional operator. This operator modifies all elements in the specified array field that match the update criteria.

Syntax

db.collection.update(
    { "matchCondition": "value" },
    { $set: { "arrayField.$[]": "newValue" } }
);

Sample Data

Let us first create a collection with documents ?

db.demo385.insertOne({
    "ServerLogs": [
        {
            "status": "InActive"
        },
        {
            "status": "InActive"
        },
        {
            "status": "InActive"
        }
    ]
});

{
    "acknowledged": true,
    "insertedId": ObjectId("5e5b6a7522064be7ab44e7f5")
}

Display all documents from the collection ?

db.demo385.find().pretty();

{
    "_id": ObjectId("5e5b6a7522064be7ab44e7f5"),
    "ServerLogs": [
        {
            "status": "InActive"
        },
        {
            "status": "InActive"
        },
        {
            "status": "InActive"
        }
    ]
}

Example: Update All Array Elements

Following is the query to update multiple elements in an array in MongoDB ?

db.demo385.update(
    { "_id": ObjectId("5e5b6a7522064be7ab44e7f5") },
    { "$set": { "ServerLogs.$[].status": "Active" }}
);

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

Verify Result

Display all documents to verify the update ?

db.demo385.find().pretty();

{
    "_id": ObjectId("5e5b6a7522064be7ab44e7f5"),
    "ServerLogs": [
        {
            "status": "Active"
        },
        {
            "status": "Active"
        },
        {
            "status": "Active"
        }
    ]
}

Key Points

• The $[] operator updates all array elements regardless of their current values.
• Use $[<identifier>] with arrayFilters for conditional updates on specific elements.
• The update affects the entire array field in the matched document.

Conclusion

The $[] all positional operator provides an efficient way to update multiple array elements simultaneously. It's ideal when you need to apply the same modification to every element in an array.