By default MongoDB creates an index on the _id (ObjectId) field, but we can easily add indexes to other fields.

Using the JavaScript shell

In the JavaScript shell simply call ensureIndexUsing the 10gen drivers in C#

In C# using the 10gen drivers we can create an index using the following

collection.EnsureIndex(new IndexKeysBuilder().Ascending("artist"));

where collection is

MongoCollection<CD> collection = db.GetCollection<CD>("cds");

To remove an index we can simply use

collection.DropIndex(new IndexKeysBuilder().Ascending("Artist"));