Domain Design Question

Question

I am working on an application where I can have Teacher, Student etc role. Some of the functionality is similar so I also have a base class User. User contains AddRole method and other stuff.

Now, I want that when the Teacher object is created the "Teacher" role is automatically assigned to the object. I am doing this inside the constructor but I think it is ugly. Here is the code:

public class Teacher : User
    {
        public Teacher()
        {
            AddRole(new Role() { RoleName = "Teacher"});
        }
    }

There is no Teacher table in the database. Everything is User based. Teacher is just a Role and have different functionality then a Student.

How would I go about this?

Answer 1

How does it work in your domain model? Whatever works for your domain model should be in your code.

Answer 2

How about

//C++ look alike pseudocode 
   public class User{
      String role;

      User (role_){role = role_;}

      String getRole(){return role;}

   }


    public class Teacher : User
        {
            public Teacher():User("Teacher")
            {

            }
        }

Answer 3

It's actually quite common to have a Role table that has a 1-to-m or m-to-m relationship with the User table.

The implementation depends highly on how your roles are going to be used. Do they have functions associated with them? Or are they just labels? Are your roles fixed or dynamic? Depending on how they're used and defined, interfaces or inheritance might work for your roles, or actual Role objects might be better.