Compiled LINQ Queries

[John Gathogo]

Lets start here. I have the following two classes:

public class Order
{
    public Int32 Id { get; set; }
    public String OrderNumber { get; set; }
    public DateTime OrderDate { get; set; }
    public String OrderStatus { get; set; }
    public Int32 CustomerId { get; set; }
    public List<OrderItem> Items { get; set; }
    public Decimal Total { get; set; }
}

public class OrderItem
{
    public Int32 OrderId { get; set; }
    public Int32 OrderLineNumber { get; set; }
    public Int32 ItemId { get; set; }
    public Double OrderQty { get; set; }
    public Decimal Price { get; set; }
    public Decimal LineTotal { get; set; }
}

Here is some LINQ query that am using to fetch Orders from two database tables (OrderMaster and OrderDetail) and return a List<Order>. The LINQ DataContext that has the two tables is named TempContext.

    static List<Order> GetOrders()
    {
        using (var context = new TempContext())
        {
            return (from om in context.OrderMasters
                    select new Order
                    {
                        Id = om.OrderID,
                        OrderNumber = om.OrderNumber,
                        OrderDate = om.OrderDate,
                        OrderStatus = om.OrderStatus,
                        CustomerId = om.CustomerID,
                        Total = om.Total,
                        Items = (from od in context.OrderDetails.Where(d => d.OrderID == om.OrderID)
                                 select new OrderItem
                                 {
                                     OrderLineNumber = od.OrderLineNumber,
                                     OrderId = od.OrderID,
                                     ItemId = od.ItemID,
                                     OrderQty = od.OrderQty,
                                     Price = od.Price,
                                     LineTotal = od.Total
                                 }).ToList()
                    }).ToList();
        }
    }

My idea is to convert this LINQ Query to a Compiled LINQ Query and see whether I will be able to get any notable improvements on execution performance. Here is what I was able to