using System;
using System.Linq;
using Microsoft.Data.Entity;

namespace SoTestConsole
{
    public class Foo
    {
        public long Id { get; set; }
        public string Descr { get; set; }
    }

    public class FooContext : DbContext
    {
        public DbSet<Foo> Foos { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFStackOverFlowTest;Trusted_Connection=True;");
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Foo>().HasKey(x => x.Id);
            modelBuilder.Entity<Foo>().Property(x => x.Id).ValueGeneratedNever();
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            using (var db = new FooContext())
            {
                var myFoo = new Foo {Id = 1002, Descr = "Test"};
                db.Add(myFoo);
                db.SaveChanges();
            }
            using (var db = new FooContext())
            {
                var myFoo = db.Foos.FirstOrDefault(x => x.Id == 1002);
                Console.WriteLine($"id = {myFoo?.Id}, descrip = {myFoo?.Descr}");
            }
        }
    }
}