RavenDB: How can I properly index a cartesian product in a map-reduce?
问题 This question is a spin-off of RavenDB: Why do I get null-values for fields in this multi-map/reduce index?, but I realized, the problem was another. Consider my extremely simplified domain, rewritten to a movie rental store scenario for abstraction: public class User { public string Id { get; set; } } public class Movie { public string Id { get; set; } } public class MovieRental { public string Id { get; set; } public string MovieId { get; set; } public string UserId { get; set; } } It's a