Hi, I am working with MongoDB with Go Driver v2, but I’ve encountered a strange problem. When I insert one record to the database, I use primitve.NewObjectID() to assign a new ID, but it becomes Binary.createFromBase64('<HEX Value>', 0).

My Model:

type Event struct {
	ID            primitive.ObjectID `bson:"_id,omitempty"`
	Title         string
}

My insert snippet:

event := model.Event{
		ID:            primitive.NewObjectID(),
		Title:         "New Event",
	}

	if _, err := client.Database(<DB_NAME>).Collection("events").InsertOne(ctx, event); err != nil {
		panic(err)
	}

When I print out the event model in Golang, it shows ObjectID, which is correct:

fmt.Printf("Data Type: %T, Data Value: %v", event.ID, event.ID)

Data Type: primitive.ObjectID, Data Value: ObjectID("67b06afea7becf9aeca2c397")

But when I retrive data in database, it shows otherwise:

db.events.findOne({})

{
  _id: Binary.createFromBase64('Z7Bp/imGeLj5GWHk', 0),
  title: 'New Event',
}

Also, when I retrive this data by findOne({}) with Golang, it could successfully decode to ObjectId, but it’s weird that it was stored in binary in the DB. If I don’t specify the ID field, the DB will generate a new ObjectID for me, which is ObjectID not binary. So I thought there might be some problems.

Does anyone also encounter this problem? How do you solve it?

Versions:
go - 1.24
go driver - v2.0.0
mongodb version - v8.0.4