Looks like I have found one solution. I had 2 definitions for the classes Mcq and TrueFalse, one in separate files named mcq.rb and true_false.rb and another definition in the file question.rb (the abstract class itself). I had to have these definitions in 2 files because otherwise I couldn't call the concrete classes directly without first loading the abstract class. But that apart, my has_many relation was not in the abstract class file. So it was not getting loaded when I issued the find statement on the abstract class. But if I issue the find on the concrete class directly (without calling the abstract class before) it would've loaded the has_many by then and would load the relations properly. Bit tricky. To be on the safer side now I have moved all my definitions to the abstract class file and keeping the concrete class files empty.
-subbu On Sep 9, 10:45 pm, Subbu <[EMAIL PROTECTED]> wrote: > This could have been solved earlier. But I couldn't find a solution. > > Lets say I have an abstract base model called 'Question' and sub- > models like Mcq, TrueFalse and FillInTheBlank. Mcq and TrueFalse > models have a has_many relation with another model named 'Choice' > whereas FillInTheBlank model doesn't have this. So I have defined the > choice relation in Mcq and TrueFalse class. While instantiating the > Mcq and TrueFalse classes in my controllers I don't know which class > the instance is going to belong (all I know is it doesn't belong to > FillInTheBlank). So I call it like 'Question.find(params[:id])'. Due > to the 'type' column I get either an 'Mcq' instance or a 'TrueFalse' > instance. Perfect. But the code breaks down when I call choices method > on this new instance. It says "NoMethodError: undefined method > `choices' for #<Mcq:0x3046a84>" > > However this problem doesn't come up if I call the find method on the > correct class i.e. Mcq.find() directly. But as I said earlier the > problem is I don't know whether the question is going to be a Mcq or a > TrueFalse. > > One dirty solution I tried is to call find on the abstract class > (Question.find()), get value of 'type' attribute and issue another > find statement on the correct class (Mcq.find()). But even that didn't > solve the problem. > > Has anybody faced this kind of a problem? Can someone point me in the > right direction? > > Thanks much. > subbu --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
