asp.net mvc - Soc in MVC which is the better design pattern for mvc for huge distributed applications -

i need create e-commerce application ,which best design model
have seen of them separating entity framework context class in seperate class library , business layer in seperate class library , data classes poco class in seperate class library project. have context class know consider example

this db created poco class

 using system.componentmodel.dataannotations;  using system.web.mvc;    public partial class user   {   public int userid { get; set; }   public string username { get; set; }     public string password { get; set; }  public string confirmpassword { get; set; }    public string fullname     { get; set; }           public string emailid { get; set; }                 }  [httppost]             [validateantiforgerytoken]             public actionresult register(user u)             {                 if (modelstate.isvalid)                 {                     using (mydatabaseentities dc = new mydatabaseentities())                     {                         dc.users.add(u);                         dc.savechanges();                         modelstate.clear();                         u = null;                         viewbag.message = "successfully registration done";                     }                 }                 return view(u);             } 

or else have create seperate class container , access?

 public class user   {       public int userid { get; set; }      public string username { get; set; }        public string password { get; set; }     public string confirmpassword { get; set; }       public string fullname  { get; set; }  *     public string emailid { get; set; }                         }  

in controller

public actionresult register(user u)             {                                   using (mydatabaseentities dc = new mydatabaseentities())                     {                           user.userid= u.userid;                         user.username = u.username;                          user. password = u.password;                         user.confirmpassword = u.confirmpassword;                        user.userid= u.userid;                                              dc.savechanges();                         viewbag.message = "successfully registration done";                     }                 }                 return view(u);             } 

which better way , difference between model binding , these? why not preferred binding ef classes?

second way - when separate dal (data access layer) , viewmodels bind in controller automatically mvc better.

because if separate atleast 2 layers (i can't see bl layer in example) can change views show user information , don't mess dal layer, change mappings (you map viewmodel in register controller).

this looks insignificant if have simple view , dal logic, when project grow good, because this allow change view logic , dal logic separately.