// @nuget: EntityFramework

​

using System;

using System.Data.Entity;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        using (var context = new EntityContext())

        {

            context.Database.Log = Console.Write;

            using (DbContextTransaction transaction = context.Database.BeginTransaction())

            {

                try

                {

                    List<Customer>  customerList = new List<Customer>()

                    {

                        new Customer() { Name ="John"},

                        new Customer() { Name ="Andy"},

                        new Customer() { Name ="Mark"}

                    };

                    context.Customers.AddRange(customerList);

                    context.SaveChanges();

                    context.Invoices.Add(new Invoice() { Date = DateTime.Now.AddDays(-107), CustomerID = 1});

                    context.SaveChanges();

                }

                catch (Exception ex)

                {

                    transaction.Rollback();

                    Console.WriteLine("Error occurred.");

                }

            }

        }

    }

​

    public class EntityContext : DbContext

    {

        public EntityContext() : base(FiddleHelper.GetConnectionStringSqlServer())

        {

​

        }

        public DbSet<Customer> Customers { get; set; }

        public DbSet<Invoice> Invoices { get; set; }

    }

    public class Customer

    {

        public int CustomerID { get; set; }

        public string Name { get; set; }

        public virtual List<Invoice> Invoices { get; set; }

    }

    public class Invoice

    {

        public int InvoiceID { get; set; }

        public DateTime Date { get; set; }

        public int CustomerID { get; set; }

        public virtual Customer Customer { get; set; }

        public virtual ICollection<Item> Items { get; set; }

    }

    public class Item

    {

        public int ItemID { get; set; }

        public string Name { get; set; }

        public int InvoiceID { get; set; }

        public virtual Invoice Invoice { get; set; }

    }

}