public void BulkUpsert() { var range = 10; var dtos = Enumerable.Range(0, range).Select(i => new LocationDto { City = i.ToString(), Latitude = 1.0, Longitude = 3.0, Zip = i.ToString(), Extra = new[] { 10, 12 }, AnnoyingInterface = new AnnoyingInterface() }).ToArray(); using (var conn = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySql"].ConnectionString)) { conn.Open(); conn.BulkUpsert(dtos.Take(5).ToArray()); conn.BulkUpsert(dtos); for (int i = 0; i < range; i++) { var dto = conn.Query <LocationDto>( q => q.Where(w => w.Equal(x => x.Zip, i.ToString())) ).FirstOrDefault(); Assert.That(dto.City, Is.EqualTo(i.ToString())); } } }