Beginners' guide to using MongoDB 4.0.2 and the official C# driver

using System;
using System.Linq;

namespace TestMongo
{
    using MongoDB.Driver;
    using MongoDB.Driver.Builders;
    using MongoDB.Driver.Linq;

    public partial class Program
    {
        public static void DemoQueryBuilder( MongoServer server,  MongoDatabase database,MongoCollection<ClubMember> collection)
        {
            DateTime membershipDate = DateTime.Now.AddYears(-5);

            //DateTime is stored in BsonElement as a UTC value so need to convert
            var recentMembers = collection.Find(Query.GT("MembershipDate", membershipDate.ToUniversalTime()));
            Console.WriteLine("Members who have joined in the last 5 years ...");
            foreach (ClubMember clubMember in recentMembers)
            {
                clubMember.PrintDetailsToScreen();
            }
            //This 'Find' should be efficient as it will use the index 'myIndex'
            //For finding and sorting
            var jonesRees =
                collection.Find(Query.Or(Query.EQ("Lastname", "Rees"), Query.EQ("Lastname", "Jones"))).SetSortOrder(
                    SortBy.Ascending("Lastname", "Forename").Descending("Age"));
            Console.WriteLine("Members named Jones or Rees ...");
            foreach (ClubMember clubMember in jonesRees)
            {
                clubMember.PrintDetailsToScreen();
            }
            int result2 =
                collection.AsQueryable().Select(c => c).Count(c => c.Lastname == "Jones" && c.Forename == "David");
            Console.WriteLine("The number of members named David Jones is {0}", result2);

            //The following 'using' statement makes sure all database traffic is  on the same thread
            // This is necessary because the newly written data is being queried straight away.
            // This can give rise to concurrency problems if different threads are used
            using (server.RequestStart(database))
            {
                //Change the name of every David Jones to Dai Jones
                IMongoQuery davidJonesQuery = Query.And(Query.EQ("Lastname", "Jones"), Query.EQ("Forename", "David"));
                UpdateBuilder update = Update.Set("Forename", "Dai");
                collection.Update(davidJonesQuery, update, UpdateFlags.Multi);

                IQueryable<ClubMember> result3 =
                    collection.AsQueryable().Where(c => (c.Lastname == "Jones" && c.Forename == "Dai"));
                foreach (ClubMember name in result3)
                {
                    name.PrintDetailsToScreen();
                }
            }

        }
    }
}