C# Online Compiler | .NET Fiddle

// Entity Framework Classic
// Doc: https://entityframework-classic.net/bulk-update

// @nuget: Z.EntityFramework.Classic


using System;
using System.Collections.Generic;
using System.Linq;
using System.Data.Entity;
public class Program
{
	public static void Main()
	{
		GenerateCustomers(5);

		using(var context = new EntityContext())
		{
			FiddleHelper.WriteTable("1 - Before BulkUpdate", context.Customers.AsNoTracking().ToList());	
			
			var customerUpdated = context.Customers
				.Where(x => x.CustomerID < 5)
				.UpdateFromQuery( x => new Customer { FirstName = "foo" } );
			
			FiddleHelper.WriteTable("2 - After BulkUpdate", context.Customers.AsNoTracking().ToList());	
		}
	}
		 
	public static List<Customer> GenerateCustomers(int count)
	{
		var list = new List<Customer>();
		
		for(int i = 0; i < count; i++)
		{
			list.Add(new Customer() { Code = "Code_" + i, FirstName = "FirstName_" + i, LastName = "LastName_" + i, NotUpdated = "NotUpdated_" + i });
		}
		
		using (var context = new EntityContext())
		{
			context.BulkInsert(list);
		}
		
		return list;
	}

	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 Code { get; set; }
		public string FirstName { get; set; }
		public string LastName { get; set; }
		public string NotUpdated { get; set; }
	}
}

 
// Entity Framework Classic
// Doc: https://entityframework-classic.net/bulk-update
​
// @nuget: Z.EntityFramework.Classic
​
​
using System;
using System.Collections.Generic;
using System.Linq;
using System.Data.Entity;
public class Program
{
    public static void Main()
    {
        GenerateCustomers(5);
​
        using(var context = new EntityContext())
        {
            FiddleHelper.WriteTable("1 - Before BulkUpdate", context.Customers.AsNoTracking().ToList());    
            
            var customerUpdated = context.Customers
                .Where(x => x.CustomerID < 5)
                .UpdateFromQuery( x => new Customer { FirstName = "foo" } );
            

Cached Result