Entity Framework – Entity Framework 4.1: the navigation property ‘businessuser’ declared on the ‘Login’ type has configured the multiplicity of conflicts

I have two entities

BusinessUser { Id(PK),Name,...}

Login { BusinessUserID(PK,FK),Email,Password,etc...}

The relationship between businessuser and login is one to many / one

I have the following configuration in the businessuser EF configuration class

this.HasOptional(bu => bu.LoginInfo)
    .WithOptionalPrincipal(l => l.BusinessUser);

In the login EF configuration class

this.Hasrequired(l => l.BusinessUser)
    .WithOptional(bu => bu.LoginInfo);

I got the following exception

I first use my one to one / zero configuration error in EF 4.1 code

Update 1: the following is my class structure

public class BusinessUser {
    public virtual int ID { get; set; }

    public virtual int BusinessID { get; set; }

    public virtual Business Business { get; set; }

    public Login LoginInfo { get; set; }
  }

 public class Login {
    public virtual int BusinessUserID { get; set; }

    public virtual string Email { get; set; }

    public virtual string Password { get; set; }

    public BUsinessUser BusinessUserInfo { get; set; }
  }

I'm also looking for a two-way

Solution

Your businessuser must configure the relationship to:

this.HasOptional(bu => bu.LoginInfo)
    .Withrequired(l => l.BusinessUser);

The two configurations must be the same (actually only one is required) and the first configuration is incorrect because it attempts to define 0 1 – 0.. 1. Relationship