Insert Documents

Overview

In this guide, you can learn how to insert documents into a MongoDB collection.

Before you can find, update, and delete documents in MongoDB, you must insert those documents. You can insert one document by using the InsertOne() method, or insert multiple documents by using either the InsertMany() or BulkWrite() method.

The following sections focus on InsertOne() and InsertMany(). To learn how to use the BulkWrite() method, see the Bulk Operations guide.

The _id Field

In MongoDB, each document must contain a unique _id field.

The two options for managing this field are:

• Managing this field yourself, ensuring that each value you use is unique.

• Letting the driver automatically generate unique ObjectId values. The driver generates unique ObjectId values for documents that you do not explicitly specify an _id.

Unless you provide strong guarantees for uniqueness, MongoDB recommends you let the driver automatically generate _id values.

To learn more about the _id field, see the Server Manual Entry on Unique Indexes.

To learn more about document structure and rules, see the Server Manual Entry on Documents.

Insert a Document

Use the InsertOne() method to insert a single document into a collection.

Upon successful insertion, the method returns an InsertOneResult instance that contains the _id of the new document.

type Book struct {
	Title  string
	Author string
}

coll := client.Database("db").Collection("books")
doc := Book{Title: "Atonement", Author: "Ian McEwan"}
result, err := coll.InsertOne(context.TODO(), doc)
fmt.Printf("Inserted document with _id: %v\n", result.InsertedID)

Inserted document with _id: ObjectID("...")

opts := options.InsertOne().SetBypassDocumentValidation(true)

Insert Multiple Documents

Use the InsertMany() method to insert multiple documents into a collection.

Upon successful insertion, the InsertMany() method returns an InsertManyResult instance that contains the _id fields of the inserted documents.

coll := client.Database("myDB").Collection("favorite_books")
docs := []interface{}{
    Book{Title: "Cat's Cradle", Author: "Kurt Vonnegut Jr."},
    Book{Title: "In Memory of Memory", Author: "Maria Stepanova"},
    Book{Title: "Pride and Prejudice", Author: "Jane Austen"},
}
result, err := coll.InsertMany(context.TODO(), docs)
fmt.Printf("Documents inserted: %v\n", len(result.InsertedIDs))
for _, id := range result.InsertedIDs {
    fmt.Printf("Inserted document with _id: %v\n", id)
}

Documents inserted: 3
Inserted document with _id: ObjectID("...")
Inserted document with _id: ObjectID("...")
Inserted document with _id: ObjectID("...")

opts := options.InsertMany().SetBypassDocumentValidation(true).SetOrdered(false)

{ "_id": 1, "title": "Where the Wild Things Are" }
{ "_id": 2, "title": "The Very Hungry Caterpillar" }
{ "_id": 1, "title": "Blueberries for Sal" }
{ "_id": 3, "title": "Goodnight Moon" }

type Book struct {
    ID    int `bson:"_id"`
    Title string
}
...
docs := []interface{}{
    Book{ID: 1, Title: "Where the Wild Things Are"},
    Book{ID: 2, Title: "The Very Hungry Caterpillar"},
    Book{ID: 1, Title: "Blueberries for Sal"},
    Book{ID: 3, Title: "Goodnight Moon"},
}
result, err := coll.InsertMany(context.TODO(), docs)
if err != nil {
    fmt.Printf("A bulk write error occurred, but %v documents were still inserted.\n", len(result.InsertedIDs))
}
for _, id := range result.InsertedIDs {
    fmt.Printf("Inserted document with _id: %v\n", id)
}

A bulk write error occurred, but 2 documents were still inserted.
Inserted document with _id: 1
Inserted document with _id: 2

{ "_id": 1, "title": "Where the Wild Things Are" }
{ "_id": 2, "title": "The Very Hungry Caterpillar" }

Additional Information

For runnable examples of the insert operations, see the following usage examples:

• Insert a Document Example

• Insert Multiple Documents

To learn more about performing the operations mentioned, see the following guides:

• Specify a Query

• Bulk Operations