Building an Agile SQL Data Access Layer

using System;
using System.Collections.Generic;
using System.Text;

namespace InMemoryDal.Entities
{
    public class OrderItem
    {
        private int quantity;
        private Guid id;
        private Order containingOrder;
        private Product product;
        
        [EntityKey, Persistable, Searchable]
        public Guid Id
        {
            get { return id; }
            set { id = value; }
        }

        [Persistable, Searchable]
        public Product Product
        {
            get { return product; }
            set { product = value; }
        }

        [Persistable, Searchable]
        public Order ContainingOrder
        {
            get { return containingOrder; }
            set { containingOrder = value; }
        }

        [Persistable, Searchable]
        public int Quantity
        {
            get { return quantity; }
            set { quantity = value; }
        }

        public decimal Total
        {
            get
            {
                return quantity * product.Price;
            }
        }
    
    }
}