// @nuget: Microsoft.EntityFrameworkCore.SqlServer

// @nuget: Z.EntityFramework.Extensions.EFCore

​

using Microsoft.EntityFrameworkCore;

using System;

using System.Collections.Generic;

using System.Linq;

using Microsoft.Data.SqlClient;

public class Program

{

    public static void Main()

    {

        using (var context = new EntityContext())

        {

            context.Database.EnsureCreated();

        }

        var invoices = GenerateInvoices(2000, 5);

        using (var context = new EntityContext())

        {

            // context.BulkInsert(invoices, options => options.IncludeGraph = true);

        }   

    }

    public static List<Invoice> GenerateInvoices(int countInvoice, int countInvoiceItem) 

    {

        List<Invoice>  list = new List<Invoice>();

        for(int i = 0; i < countInvoice; i++)

        {

            var invoice = new Invoice() { Number = "Number_" + i, C1 = "C1_" + i, C2 = "C2_" + i, C3 = "C3_" + i, C4 = "C4_" + i, C5 = "C5_" + i, Items = new List<InvoiceItem>() };

            list.Add(invoice);

            for(int j = 0; j < countInvoiceItem; j++)

            {

                invoice.Items.Add(new InvoiceItem() { ProductName = "ProductName_" + i + "_" + j, C1 = "C1_" + i, C2 = "C2_" + i, C3 = "C3_" + i, C4 = "C4_" + i, C5 = "C5_" + i  });

            }

        }

        return list;

    }

​

    public class EntityContext : DbContext

    {

        public EntityContext() 

        {

        }

​

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

        {

            optionsBuilder.UseSqlServer(new SqlConnection(FiddleHelper.GetConnectionStringSqlServer()));

​

            base.OnConfiguring(optionsBuilder);

        }

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

        public DbSet<InvoiceItem> InvoiceItems { get; set; }

    }

    public class Invoice

    {

        public int InvoiceID { get; set; }

        public string Number { get; set; }

        public List<InvoiceItem> Items { get; set; }

        public string C1 { get; set; }

        public string C2 { get; set; }

        public string C3 { get; set; }

        public string C4 { get; set; }

        public string C5 { get; set; }

    }

    public class InvoiceItem

    {

        public int InvoiceItemID { get; set; }

        public string ProductName { get; set; }

        public Invoice Invoice { get; set; }

        public string C1 { get; set; }

        public string C2 { get; set; }

        public string C3 { get; set; }

        public string C4 { get; set; }

        public string C5 { get; set; }

    }

}