How to define a complex (1 to 0|n) entity framework relationship with fluent api?

Question

I have the following (simplified) classes:

public class Person
{
   public string Id {get; set;}  //Ignore the fact that the Id is string -- legacy system
   public string Firstname {get; set;}
   public ICollection<Member> Memberships {get; set;}
   ...
}

public class Account
{
   public string Id {get; set;}
   public string AccountType {get; set;}
   ...
}

public class Member
{
   public string AccountNumber {get; set;}
   public string PersonNumber {get; set;}
   public Account Account {get; set;}
   public Person Person {get; set;}
   ...
 }

and the following EF configuration:

//In Accounts configuration class
ToTable("missacct");
HasKey(a => a.Id);

//In Members Configuration class
ToTable("members");
HasKey(a => new { a.AccountNumber, a.PersonNumber});
HasRequired(a => a.Person).WithMany().HasForeignKey(p => p.PersonNumber);
HasRequired(a => a.Account).WithMany().HasForeignKey(a => a.AccountNumber);

//In Persons Configuration Class
ToTable("person");
HasKey(p => p.Id);
HasMany(p => p.Memberships).WithOptional().HasForeignKey(p => p.PersonNumber);

The intent here is that there are persons and accounts. An account can not exist without members and a member is always a person. But, a person can exist without being a member of an account.

The idea is I want to be able to query the following:

1. Given a specific account number I want to find all the people on the account.
2. Given a first/last name combination I want to find all persons with matching names and any accounts that they may be members of.

What I have does not currently seem to work. I'm getting a circular reference error but I'm not quite sure where I've gone wrong.

Thanks for any help you can offer!

Answer 1

You are defining two separate relationships instead of one bidirectional relationship. Try this:

//In Accounts configuration class
ToTable("missacct");
HasKey(a => a.Id);

//In Members Configuration class
ToTable("members");
HasKey(a => new { a.AccountNumber, a.PersonNumber});
HasRequired(m => m.Person).WithMany(p => p.Memberships).HasForeignKey(p => p.PersonNumber);
HasRequired(m => m.Account).WithMany().HasForeignKey(a => a.AccountNumber);

//In Persons Configuration Class
ToTable("person");
HasKey(p => p.Id);
HasMany(p => p.Memberships).WithOptional(m => m.Person).HasForeignKey(p => p.PersonNumber);

An account can not exist without members ...

You will have to enforce this part in your application logic. At relationship level you can only say that a member must have an account.