Question

I’m thinking to develop a web / mobile application with MVC4. For what I know about ASP.NET MVC, it works great when you have a 1 to 1 relationship between a table and a model class, while I had some problems when you need to work with normalized database.

—UPDATE—

Even if in the past I used Linq to SQL, I’m thinking to use Entity Data Model (not sure yet, but it seems better at the first glance).

—

A stupid example:

**table person**
ID
Name
Surname
HairColorID

**table hairColor**
HairColorID
Color

I wish to know if a situation like that can be easily solved in MVC4, without too much code writing in order to map manually all the table. I mean, I don’t know if there are some easy ways to have in my Controllers something like:

public ActionResult About(Person person)

where person automatically join my two tables.

Answer 1

I break my application into several different layers using different projects.

• My AppName.Data project handles all of my data access (i.e. retrieving data from the database).
• My AppName.Models project houses all of the view model classes and
  other model classes that I will need for my app.
• My AppName.Web project is simply the MVC web app
• My AppName.Services project handles all of my business logic and communication between the web layer and the data layer. It builds the view models, handles data validation, etc. I never call a controller action method with an actual database object. I always use view models. That view model ONLY contains what I need to populate my view.

So, in this instance, what I would do if this was a read-only view is create an AboutPersonDisplayViewModel that looks like the following:

public class AboutPersonDisplayViewModel
{
    public int PersonID { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public string HairColor { get; set; }
}

And if it were an editable view, I would have a separate view model like this:

public class AboutPersonEditViewModel
{
    public int PersonID { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public int HairColorID { get; set; }
    public IDictionary<int, string> HairColorOptions { get; set; }
}

In the database, you should have a relationship between the person and hairColor tables. So, when you build your view model, you simple get the person for the ID you want to look up and populate the AboutPersonViewModel with that person’s information and use the navigation properties to navigate to Person.HairColor to get the hair color for the ID stored.

Then, when I save, the service layer would validate the data and properly map/save the hair color chosen.

I hope this helps