3 layered & Linq to Sql - Business entities

Question

As per my understaning, 3 layered model is of UI, BLL and DAL. Now am assuming that writing insertData() funcationality, in this case i'll bind all UI-controls value to Business Entity and pass to the BLL --> DAL(since busines entity accessible to all 3 layers). let DAL replace with Linq to SQL, and now i have confusion , Linq to SQL will create classes (equalent to Business enitity) also i ahve business entity on the otherhand in my projects solution,

Q1) Do i need to have both B-entity and L2S classes? Q2) is it possible to remove business entity and L2S classes to use in the same way? if so how? Q3) better idea?

Thanks for help.

Yogesh

Answer 1

It is possible to use POCOs (your BLL layer classes) with Linq to SQL; Google around for "Linq to SQL POCO" (here is one blog post).

If you are starting a new project, it may also be worth looking in to the Entity Framework instead of Linq to SQL (or if you can use non-MS libraries, maybe even NHibernate; The 3.0 release just came out, I believe it supports Linq).