// Entity Framework Extensions

// Doc: https://entityframework-extensions.net/column-primary-key-expression

​

// @nuget: EntityFramework

// @nuget: Z.EntityFramework.Extensions

​

using System.Linq;

using System.Data.Entity;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        GenerateData();

        var list = new List<Customer>() {   new Customer () { Name = "Customer_B", Description = "Updated_B", Login = "Login2", Password = "Password2" },

            new Customer() { Name ="Customer_C", Description = "Description", Login = "Login3", Password = "Password3" }};

        // Column Primary Key: Specify custom keys 

        using (var context = new EntityContext())

        {

            context.BulkMerge(list, options => options.ColumnPrimaryKeyExpression = customer => new { customer.Login, customer.Password });

            FiddleHelper.WriteTable(context.Customers.ToList());

        }

    }

    public static void GenerateData()

    {

        using (var context = new EntityContext())

        {

            context.Customers.Add(new Customer() { Name ="Customer_A", Description = "Description", Login = "Login1", Password = "Password1" });

            context.Customers.Add(new Customer() { Name ="Customer_B", Description = "Description" , Login = "Login2", Password = "Password2" });

            context.BulkSaveChanges();  

        }

        using (var context = new EntityContext())

        {

            FiddleHelper.WriteTable(context.Customers.ToList());    

        }

    }

    public class EntityContext : DbContext

    {

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

        {

​

        }

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

    }

    public class Customer

    {

        public int CustomerID { get; set; }

        public string Name { get; set; }

        public string Description { get; set; }

        public string Login  { get; set; }

        public string Password { get; set; }

    }

}