Find the design flaw previous: The RavenDB launch video next: Porting MVC Music Store to Raven: Porting the HomeController, the Right Way This method has a design flaw, can you see it? Hint, it is using the yield keyword. Comments 05/22/2010 07:34 AM by ashic It's returning an IEnumerable using yield. The caller would take out the ones they need. There's no sense in passing parameters like limit as it would the the callers' responsibility to get only the number they need. IEnumerable won't trigger data access until and unless the data is required and so the limit parameter doesn't have any use. 05/22/2010 07:44 AM by James Newton-King An endId and limit seem at odds with one another. 05/22/2010 08:40 AM by Ayende Rahien Ashic, Yep! 05/22/2010 08:41 AM by Ayende Rahien James, startId: 1 endId: 100000 limit: 100 05/22/2010 08:55 AM by Chojrak I'd change it to IEnumerable <dictionary<int,jsondocument> , I think key-value dependencies are better handled using Dictionary. Any ideas? 05/22/2010 08:56 AM by Chojrak Oh no, damned HTML. Again: I'd change it to IEnumerable<Dictionary<int,JsonDocument>> I think key-value dependencies are better handled using Dictionary. Any ideas? 05/22/2010 08:58 AM by Ayende Rahien Chojrak, It isn't key value. It is a tuple, it isn't a set of int to json doc, it is a int & json doc. 05/22/2010 09:38 AM by Patrik This might be personal preference but I really don't like methods exposing tuple types. Create a type (possibly a struct) that has carries some semantics instead of the tuple. Note that this in C#, this would obviously not be my thoughts if the language was F#, Haskell, Erlang or any other functional language. 05/22/2010 09:42 AM by James Newton-King Is the collection between the startId and endId not continuous? A limit would make sense then. 05/22/2010 09:54 AM by Ayende Rahien James, Yes, the collection may not be continuous 05/22/2010 09:54 AM by Ayende Rahien Patrik, This is mostly for internal API needs, it just doesn't make sense to create a type here, it wouldn't add enough meaning 05/22/2010 09:56 AM by Andrew Is it not also bad practice to publicly expose IEnumerable for methods like this ? 05/22/2010 10:03 AM by Ayende Rahien Andrew, I disagree with that quite strongly 05/22/2010 10:19 AM by Andrew Yeah now that I've thought it through, I'm unsure why I even said that. I read something like this on someone's blog recently and haven't had time to process it. 05/23/2010 11:56 PM by Dmitriy Nagirnyak When using 'yield' the resulting items will be returned 'lazily' (delayed execution). This might not be what the method is intended to do. I think the intention is to have the results ready after the call. It also might have potential issue when the underlying data store is closed and the enumeration gets executed. Cheers, Dmitriy, 06/17/2010 06:27 AM by Martin R-L @Patrik, What I do in order to use the ease of tuples and other complex generic types, and get readable code, is to at least give them a friendly name by utilizing the using statement of C#. An example is given on my blog: http://goo.gl/ksCm In a specific context, you can also give the type friendly method names (like e.g. Ruby's alias methods) by using extension methods that are just simple pass-throughs. Comments have been closed on this topic.