private static DTO.Portrait GetPortraitInternal(Guid portraitId, Db4objects.Db4o.IObjectContainer container)
 {
     return container.Query<DTO.Portrait>(portrait => portrait.Guid.Equals(portraitId)).SingleOrDefault();
 }
 private static DTO.Frame GetFrameInternal(Guid frameId, Db4objects.Db4o.IObjectContainer container)
 {
     return container.Query<DTO.Frame>(frame => frame.Guid.Equals(frameId)).SingleOrDefault();
 }