C - get a handle to collection in the default database, single letter name to have nice way to transition from mgo.

CollectionWithDB - gives a reference to a collection in given database.

Connect - connects to a mongoDB instance or a cluster based on the the options provided.

ReadAllAndClose - reads all data from the cursor and closes it.

ReadOneAndClose - reads one data item from the cursor and closes it.

ReplicaSet - A replica set cluster.

Sharded - Sharded database.

Single - No cluster, single instance.

ConnOpts - options for connecting to a mongodb instance.

ConnType - type of cluster to connect to.