I am building a relatively trivial application to try to learn my way around Rails. I am having difficulty understanding how to navigate a heavily denormalized hierarchy. Could someone direct me to a bare-bones explanation of using rails to navigate database hierarchies? I am an experienced developer. Most of my work has been desktop client server, high performance, or server to server interprocess work in large scale systems (8K plus users). However, I am new to Ruby and the rails environment. Furthermore, I have never been comfortable with html development. My idea of a perfect screen is plain white that is sparsely populated with black text with a single font and no effects. The default stylesheets that rails generates are quite a bit more elaborate than I would choose to build :o) I am trying to build a flash-card application that contains quizzes, questions, possible answers, and presentations, plus historical records of users's answers over time (quiz_instances, question_instances, response_instances). I have been working from Thomas and Hansson (Agile Web D. With Rails), but I appear to be missing something in the move from the famous "depot" example into real life. I cannot for the life of me figure out how to navigate from parent objects (such as a quiz) to child objects. I find a lot of what I generally consider "fluff" - adding pictures and fonts, and tweaking positions on the screen, but I am not finding how to build controls to navigate a hierarchy. I could either be having issues with some web development fundamental, or my own misunderstanding of how Rails is supposed to work. What I have now is a skeleton that allows me to create, edit, and destroy quizzes. I have created the question controller, model, and views. However, I can't seem to be able to redirect to the list of questions from the quiz controller. I think I understand how to nest lists once I understand how to navigate a hierarchy. Since questions have no content of their own, I will also need to navigate to the presentation level to get the actual text for the question. This is a simple hierarchical structure, with the only twist being that a presentation (text, audio, and graphic) may be owned by either a quiz (preamble and postamble), a question (preamble, body, postamble), or a possible answer (body). This chart may make it more clear (or not): (quiz) 1..n (question) 1..n (possible answer) 1..n (presentation) (question.preamble) 1..1 (presentation) (question.body) 1..1 (presentation) (question.postamble) 1..1 (presentation) (quiz.preamble) 1..1 (presentation) (quiz.postamble) 1..1 (presentation) At present, I have defined quiz and question. I believe that once I have these under control I will be able to move forward. Thanks in advance. David J.
on 2006-03-09 06:35
on 2006-03-09 19:32
Hi David, you may want to look into the acts_as_tree structure
on 2006-03-10 01:03
I will try that as soon as I can. Thanks!