MongoSession.cs

    using Norm;
    using Norm.Responses;
    using Norm.Collections;
    using Norm.Linq;

    public class MongoSession {

        private string _connectionString;

        public MongoSession() {
            //set this connection as you need. This is left here as an example, but you could, if you wanted,
            _connectionString = "mongodb://127.0.0.1/MyDatabase?strict=false";
        }

        public void Delete<T>(System.Linq.Expressions.Expression<Func<T, bool>> expression) where T : class, new() {
            //not efficient, NoRM should do this in a way that sends a single command to MongoDB.
            var items = All<T>().Where(expression);
            foreach (T item in items) {
                Delete(item);
            }
        }

        public void Delete<T>(T item) where T : class, new() {
            using(var db = Mongo.Create(_connectionString))
            {
              db.Database.GetCollection<T>().Delete(item);
            }
        }

        public void DeleteAll<T>() where T : class, new() {
            using(var db = Mongo.Create(_connectionString))
            {
              db.Database.DropCollection(typeof(T).Name);
            }
        }

        public T Single<T>(System.Linq.Expressions.Expression<Func<T, bool>> expression) where T : class, new() {
            T retval = default(T);
            using(var db = Mongo.Create(_connectionString))
            {
              retval = db.GetCollection<T>().AsQueryable()
                         .Where(expression).SingleOrDefault();
            }
            return retval;
        }

        public IQueryable<T> All<T>() where T : class, new() {
            //don't keep this longer than you need it.
            var db = Mongo.Create(_connectionString);
            return db.GetCollection<T>().AsQueryable();
        }

        public void Add<T>(T item) where T : class, new() {
            using(var db = Mongo.Create(_connectionString))
            {
              db.GetCollection<T>().Insert(item);
            }
        }

        public void Add<T>(IEnumerable<T> items) where T : class, new() {
            //this is WAY faster than doing single inserts.
            using(var db = Mongo.Create(_connectionString))
            {
              db.GetCollection<T>().Insert(items);
            }
        }

        public void Update<T>(T item) where T : class, new() {
            using(var db = Mongo.Create(_connectionString))
            {
              db.GetCollection<T>().UpdateOne(item, item);
            }
        }

        //this is just some sugar if you need it.
        public T MapReduce<T>(string map, string reduce) {
            T result = default(T);
            using(var db = Mongo.Create(_connectionString))
            {
            var mr = db.Database.CreateMapReduce();
            MapReduceResponse response =
                mr.Execute(new MapReduceOptions(typeof(T).Name) {
                    Map = map,
                    Reduce = reduce
                });
            MongoCollection<MapReduceResult<T>> coll = response.GetCollection<MapReduceResult<T>>();
            MapReduceResult<T> r = coll.Find().FirstOrDefault();
            result = r.Value;
            }
            return result;
        }
    }