I am developing an application against a DB schema that I have no control over. There are tables and views in this schema with absolutely no unique ID (explicit or derived). Even using all columns as IDs would not work for these tables/views. But they do have FK relationships suitable for unidirectional mappings to other entities that I would prefer to take advantage of. Is there a strategy for mapping against tables/entities with absolutely no unique ID? I realize any solution would have to be read-only.