Entity Framework Code First: How can I create a One-to-Many AND a One-to-One relationship between two tables?

Question

Here is my Model:

public class Customer
{
    public int ID { get; set; }

    public int MailingAddressID { get; set; }
    public virtual Address MailingAd         


        

Answer 1

I know you're trying to figure out the Entity Framework way of doing this, but if I were designing this I would recommend not even wiring up MailingAddress to the database. Just make it a calculated property like this:

public MailingAddress {
   get {
      return Addresses.Where(a => a.IsPrimaryMailing).FirstOrDefault();
   }
}

Answer 2

I've struggled with this for almost the entire day and of course I wait to ask here just before finally figuring it out!

In addition to implementing the One to One as demonstrated in that blog, I also then needed to use the fluent api in order to specify the Many to Many since the convention alone wasn't enough with the One to One relationship present.

modelBuilder.Entity<Customer>().HasRequired(x => x.PrimaryMailingAddress)
    .WithMany()
    .HasForeignKey(x => x.PrimaryMailingAddressID)
    .WillCascadeOnDelete(false);

modelBuilder.Entity<Address>()
    .HasRequired(x => x.Customer)
    .WithMany(x => x.Addresses)
    .HasForeignKey(x => x.CustomerID);

And here is the final model in the database: