Entity Framework Custom Navigational Properties

Question

Is there a way to map below ClassA.BId to ClassB.BetaId ? BetaId in ClassB is not primary key. Thus, mapping in following way end up in " The ForeignKeyAttribute is not valid" exception. Note that there is no foreign key relationship in these 2 classes. For some reason I must not map ClassA.BId to ClassB.Id because these 2 field is unrelated but I need to custom map ClassA.BId to ClassB.BetaId due to these 2 field is related. However, The Id in ClassB must remain as primary key.

Note: I'm using Entity Framework 6

[Table("A")]
public class ClassA{
    [Key]
    public int Id { get; set; }


    public int BId { get; set; }

    [ForeignKey("BId")]
    public virtual B B { get; set; }
}

[Table("B")]
public class ClassB{
    [Key]
    public int Id { get; set; }

    public int BetaId { get; set; }
}

Answer 1

If B.BetaID is unique you can declare it to be the Key. Otherwise EF Core supports Foreign Key properties referencing Alternate Keys. See https://docs.microsoft.com/en-us/ef/core/modeling/alternate-keys