var prod = new Product { ID=1000, Description ="Description", Discontinued = false, LastSale = DateTime.Now };
Products.InsertOnSubmit(prod);

SubmitChanges();

prod.Discontinued = true; // здесь я не знаю, какие изменения произошли и в каких полях

SubmitChanges();

DECLARE @p0 Int SET @p0 = 1000
DECLARE @p1 VarChar(11) SET @p1 = 'Description'
DECLARE @p2 Bit SET @p2 = 0
DECLARE @p3 DateTime SET @p3 = '2010-02-25 18:11:06.789'

INSERT INTO [Product]([ID], [Description], [Discontinued], [LastSale])
VALUES (@p0, @p1, @p2, @p3)
GO

DECLARE @p0 Int SET @p0 = 1000
DECLARE @p1 Bit SET @p1 = 1

UPDATE [Product]
SET [Discontinued] = @p1
WHERE [ID] = @p0

Поддержка наследования в BLToolkit выполнена по образу и подобию наследования в Linq To SQL.

from p in db.DiscontinuedProduct
select p;

from c in db.Product
where c is Northwind.DiscontinuedProduct
select c;

from c in db.Product select c;

IT>from c in db.Product select c;
IT>

public class ProductEx : Product
{
    public int SomeValue { get; set; }
}

[TableName("Employees")]
public class Employee
{
    [PrimaryKey, NonUpdatable]
    public int EmployeeID;

    [Association(ThisKey="EmployeeID", OtherKey="EmployeeID")]
    public List<EmployeeTerritory> EmployeeTerritories;
}

[TableName("EmployeeTerritories")]
public class EmployeeTerritory
{
    [PrimaryKey]
    public int    EmployeeID;

    [PrimaryKey, NotNull]
    public string TerritoryID;

    [Association(ThisKey="EmployeeID",  OtherKey="EmployeeID")]  public Employee  Employee;
    [Association(ThisKey="TerritoryID", OtherKey="TerritoryID")] public Territory Territory;
}

[TableName("Territories")]
public class Territory
{
    [PrimaryKey, NotNull]
    public string TerritoryID;

    [Association(ThisKey="TerritoryID", OtherKey="TerritoryID")]
    public List<EmployeeTerritory> EmployeeTerritories;
}

public class Employee
{
    public int EmployeeID;
    public List<Territory> Territories;
}

public class Territory
{
    public string TerritoryID;
    public List<Employee> Employees;
}

public class Employee
{
    public int EmployeeID;

    [ManyToManyAssociation(TableName="EmployeeTerritories", ThisKey="EmployeeID", OtherKey="TerritoryID")]
    public List<Territory> Territories;
}

public class Territory
{
    public string TerritoryID;

    [ManyToManyAssociation(TableName="EmployeeTerritories", ThisKey="TerritoryID", OtherKey="EmployeeID")]
    public List<Employee> Employees;
}

static decimal? RoundToEven(decimal? value)
{
    throw new NotImplementedException();
}

static void RoundToEvenTest()
{
    Expressions.MapMember<decimal?,decimal?>(
        value => RoundToEven(value),
        value =>
            value - Sql.Floor(value) == 0.5m && Sql.Floor(value) % 2 == 0?
                Sql.Floor(value) :
                Sql.Round(value));

    using (var db = new NorthwindDB())
    {
        var query =
            from o in db.Order
            let sum = o.OrderDetails.Sum(d => d.Quantity * d.UnitPrice)
            where RoundToEven(sum) >= 10
            select o.Freight;

        foreach (var item in query)
        {
            Console.WriteLine(item);
        }
    }
}

        public T GetSingle<T>(Expression<Func<T, bool>> expression) where T : class
        {
            IQueryable<T> queryable = ((IQueryProvider)GetBltContext().GetTable<T>()).CreateQuery<T>(expression);
            var list = queryable.ToList();
            return queryable.FirstOrDefault();
        }

GetSingle<Customer>(c => c.CustomerID == "NEWCS")

G>        public T GetSingle<T>(Expression<Func<T, bool>> expression) where T : class
G>        {
G>            IQueryable<T> queryable = ((IQueryProvider)GetBltContext().GetTable<T>()).CreateQuery<T>(expression);
G>            var list = queryable.ToList();
G>            return queryable.FirstOrDefault();
G>        }
G>

return GetBltContext().GetTable<T>().Where(expression).FirstOrDefault();

db.SetSpCommand("MySprocName").ExecuteXXX();

var q = from c in db.GetTable<Customer>()
  let balance = MySql.GetCustomerBalance(c.ID)
  select new {c.ID, c.Name, balance};

var q = from c in db.GetTable<Customer>() select new { c.Name, MySql.GetCustomerBalance(c.ID) };

[SqlExpression("{0}({1})", 0, 1, ServerSideOnly=true)]
public static T SqlFunction<T>(string functionName, T p1)
{
    return p1;
}

[SqlExpression("{0}({1}, {2})", 0, 1, 2, ServerSideOnly=true)]
public static T SqlFunction<T1,T2>(string functionName, T p1, T2 p2)
{
    return obj;
}

var q = from c in db.GetTable<Customer>()
MC>  let balance = MySql.GetCustomerBalance(c.ID)
MC>  select new {c.ID, c.Name, balance};

var q = from c in db.GetTable<Customer>() select new { c.Name, MySql.GetCustomerBalance(c.ID) };

[SqlFunction(ServerSideOnly=true)]
public static double GetCustomerBalance(int ID)
{
    throw new NotInplementedException();
}

public static class MySql
{
    [SqlExpression("{0}({1})", 0, 1, ServerSideOnly = true)]
    public static TResult StoredFunction<TResult, TParameter>(string functionName, TParameter parameter)
    {
        throw new NotImplementedException();
    }
}

var q = from c in db.GetTable<Customer>()
        let func = MySql.StoredFunction<double, int>("GetCustomerBalance", c.ID)
        select new {c.ID, c.Name, func};

var q = from c in db.GetTable<Customer>()
        select new Pair(c.Name, MySql.StoredFunction<double, int>("GetCustomerBalance", c.ID));

SELECT
    c.Name,
    'GetCustomerBalance'(c.ID) as c1
FROM
    customers c

    public class Repository<T>  where T : DbManager, new()
    {
        public T Context { 
            get { return DataContext.Value; }
        }

        [ThreadStatic]        
        private volatile static Lazy<T> dataContext;

        public static Lazy<T> DataContext {
            get { return dataContext ?? (dataContext = new Lazy<T>( () => new T())); }
            set { dataContext = value; }
        }
    }

    public class NewsRepository : Repository<OlympDataContext>
    {
        public List<News> GetAllNews()
        {            
            return Context.News.ToList();
        }
    }

        protected void Application_EndRequest(object sender, EventArgs e)
        {
            var lazy = Repository<OlympDataContext>.DataContext;
            if (lazy.IsValueCreated)
            {
                lazy.Value.Dispose();
                Repository<OlympDataContext>.DataContext = null;
            }
        }

        protected void Application_BeginRequest(object sender, EventArgs e)
        {
            var lazy = new Lazy<OlympDataContext>(() => new OlympDataContext());
            Repository<OlympDataContext>.DataContext = lazy;
        }

var newsRepo = new NewsRepository();