Unique nullable index

//using NullableUniqueDemo.Migrations;
using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;

namespace NullableUniqueDemo
{
    public class Program
    {
        public static void Main()
        {
            //Database.SetInitializer<MyContext>(new MigrateDatabaseToLatestVersion<MyContext, Configuration>());

            MyContext db = new MyContext();
            db.ExampleTable.Add(new MyClass() { UniqueColumn = "One" });
            db.ExampleTable.Add(new MyClass() { UniqueColumn = "Two" });
            db.SaveChanges();

            db.ExampleTable.Add(new MyClass() { UniqueColumn = null });
            db.ExampleTable.Add(new MyClass() { UniqueColumn = null });

            // There is no exception when adding two entries with null values for the unique column.
            db.SaveChanges();

            db.ExampleTable.Add(new MyClass() { UniqueColumn = "One" });

            // Error when you add entry with non-unique 'UniqueColumn'
            db.SaveChanges();
        }
    }

    public class MyClass
    {
        public int Id { get; set; }
        public string UniqueColumn { get; set; }
    }

    public class MyContext : DbContext
    {
        public DbSet<MyClass> ExampleTable { get; set; }
    }
}


// Migration Folder
namespace NullableUniqueDemo.Migrations
{
    using System;
    using System.Data.Entity.Migrations;

    internal sealed class Configuration : DbMigrationsConfiguration<NullableUniqueDemo.MyContext>
    {
        public Configuration()
        {
            AutomaticMigrationsEnabled = false;
        }
    }
}


namespace NullableUniqueDemo.Migrations
{
    using System;
    using System.Data.Entity.Migrations;

    public partial class IndexedMigration : DbMigration
    {
        public override void Up()
        {
            CreateTable(
                "dbo.MyClasses",
                c => new
                    {
                        Id = c.Int(nullable: false, identity: true),
                        UniqueColumn = c.String(nullable: true, maxLength: 450),
                    })
                .PrimaryKey(t => t.Id);

            // Add unique nullable index
            string indexName = "IX_UQ_UniqueColumn";
            string tableName = "dbo.MyClasses";
            string columnName = "UniqueColumn";

            Sql(string.Format(@"
                CREATE UNIQUE NONCLUSTERED INDEX {0}
                ON {1}({2})
                WHERE {2} IS NOT NULL;",
                indexName, tableName, columnName));

            //CreateIndex(
            //    table: "dbo.ExampleClasses",
            //    columns: new string[] { "UniqueColumn" },
            //    unique: true,
            //    name: "IX_UniqueColumn",
            //    clustered: false,
            //    anonymousArguments: new
            //    {
            //        Include = new string[] { "UniqueColumn" },
            //        Where = "UniqueColumn IS NOT NULL"
            //    });
        }

        public override void Down()
        {
            DropIndex("dbo.MyClasses", "IX_UQ_UniqueColumn");
            DropTable("dbo.MyClasses");
        }
    }
}


// <auto-generated />
namespace ConsoleApplication8.Migrations
{
    using System.CodeDom.Compiler;
    using System.Data.Entity.Migrations;
    using System.Data.Entity.Migrations.Infrastructure;
    using System.Resources;

    [GeneratedCode("EntityFramework.Migrations", "6.1.1-30610")]
    public sealed partial class Migration5 : IMigrationMetadata
    {
        private readonly ResourceManager Resources = new ResourceManager(typeof(Migration5));

        string IMigrationMetadata.Id
        {
            get { return "201406231015119_Migration5"; }
        }

        string IMigrationMetadata.Source
        {
            get { return null; }
        }

        string IMigrationMetadata.Target
        {
            get { return Resources.GetString("Target"); }
        }
    }
}