Retrieving the first document in a MongoDB collection?

To retrieve the first document in a MongoDB collection, use the findOne() method. This returns the first document from the collection in natural insertion order.

Syntax

db.collectionName.findOne();

// Store in variable and display
var result = db.collectionName.findOne();
result;

Sample Data

db.retrieveFirstDocumentDemo.insertMany([
    {"ClientName": "Robert", "ClientAge": 23},
    {"ClientName": "Chris", "ClientAge": 26},
    {"ClientName": "Larry", "ClientAge": 29},
    {"ClientName": "David", "ClientAge": 39}
]);

{
    "acknowledged": true,
    "insertedIds": [
        ObjectId("5ca2325966324ffac2a7dc6d"),
        ObjectId("5ca2326266324ffac2a7dc6e"),
        ObjectId("5ca2326a66324ffac2a7dc6f"),
        ObjectId("5ca2327566324ffac2a7dc70")
    ]
}

Display All Documents

db.retrieveFirstDocumentDemo.find().pretty();

{
    "_id": ObjectId("5ca2325966324ffac2a7dc6d"),
    "ClientName": "Robert",
    "ClientAge": 23
}
{
    "_id": ObjectId("5ca2326266324ffac2a7dc6e"),
    "ClientName": "Chris",
    "ClientAge": 26
}
{
    "_id": ObjectId("5ca2326a66324ffac2a7dc6f"),
    "ClientName": "Larry",
    "ClientAge": 29
}
{
    "_id": ObjectId("5ca2327566324ffac2a7dc70"),
    "ClientName": "David",
    "ClientAge": 39
}

Retrieve First Document

var firstDocumentOnly = db.retrieveFirstDocumentDemo.findOne();
firstDocumentOnly;

{
    "_id": ObjectId("5ca2325966324ffac2a7dc6d"),
    "ClientName": "Robert",
    "ClientAge": 23
}

Key Points

• findOne() returns the first document in natural insertion order.
• Returns null if no documents exist in the collection.
• More efficient than find().limit(1) for retrieving a single document.

Conclusion

The findOne() method efficiently retrieves the first document from a MongoDB collection. It returns the document in natural order or null if the collection is empty.