Unfortunately I don't have the time right now to write up a full treatement of this subject, but it's important, and it just came up in the Orcas ADO.Net forum.  I took a quick stab at it in a response to a question there, and I don't want to lose track of this idea for future treatment.  If you are interested in the entity framework, you might want to read this thread: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1339491&SiteID=1