FK on Guid

  public class PiCollectiveIdentity {
    public Guid Id { get; set; } = new Guid();
    public long IdentityId { get; set; }
    public required string Name { get; set; }
    [ForeignKey("IdentityName")]
    public IList<PiCollectiveIdentityMapping> Mappings { get; set; } = new List<PiCollectiveIdentityMapping>();
  }

  public class PiCollectiveIdentityMapping{
    public Guid Id { get; set; } = new Guid();
    public DateTime CollectionDate { get; set; } = DateTime.UtcNow;
    public required string IdentityName { get; set; }
    public PiCollectiveIdentity ? Identity { get; set; } = null;
  }