RavenDB tracked changes bypasses validation

I am playing around trying to get an application framework going that uses RavenDB. I have setup a business logic service, which has a 1 to 1 relationship with a session and effectively becomes the unit of work abstraction. Part of the business logic service would be to contain all the validation. A method from the service might be something like ``` public void StoreUser(User user) { //Some validation logic if(string.IsNullOrWhiteSpace(user.Name)) throw new Exception("User name can not be empty"); Session.Store(user); } ``` The issue is that because user is tracked as soon as it is stored i can bypass any validation on the store method but storing a correct value then changing it later ``` public void TestUserStore() { var u1 = new User() {Name = "John"}; var u2 = new User() { Name = "Amy" }; Service.StoreUser(u1); u1.Name = null; //change is tracked and will persist on the next save changes Service.StoreUser(u2); Service.SaveChanges(); //The following fails, as we have stored null as the name rather than "John" bypassing our validation Assert.IsTrue(Service.AdhocQuery<User>().Any(u => u.Name == "John")); } ``` Is there someway to get RavenDB to store only a snapshot of the item that was stored and not track further changes? Should i be cloning everything going into and out of the business logic service to prevent illegal update? or am i doing the validation in the wrong place is there a better place to put this logic?