Before I respond, I think that it would be helpful if you provided your database entity–relationship model. Also, I don't see that you have a Classes, the school variety, table. Liz
On Monday, August 17, 2015 at 1:18:38 AM UTC-4, Scott Goci wrote: > > I've been wrestling with database normalization and the "Rails Way" and I > wanted to get peoples opinions as to if there's a best practices guide to > how to do it. Here's some background: > > Let's assume we have a model/schema similar to the following: > > class Student < ActiveRecord::Base > has_many :student_exams > has_many :exams, through: :student exams > end > > class StudentExam < ActiveRecord::Base > belongs_to :student > belongs_to :exam > end > > class Exam < ActiveRecord::Base > has_many :questions > belongs_to :professor > has_one :college, through: :professor > end > > class Question < ActiveRecord::Base > belongs_to :exam > has_many :responses > > # question_text: text > end > > class Response < ActiveRecord::Base > belongs_to :question > belongs_to :student > > # response_text: text > end > > class Evaluation > belongs_to :response > belongs_to :professor > > # grade: integer > end > > > The idea is that a *Professor* creates an *Exam* and* Questions*, and > then assigns students through *StudentExam* to take that exam. The > students then generate *Responses* to the exam questions, and then those > *Responses* are graded by *Evaluations* done by the *Professor*. > Now, given the above background, I wanted to ask a few questions to get > peoples opinions on how to structure this app: > > *Questions* > > 1. In general, are there any changes you guys would make with the > given associations? > 2. For the *Response* model, does it make sense to do "belongs_to > :student", or should it instead be "belongs_to :student_exam"? It > feels more logical to have the former, because we can get the exam through > the question if need be (response.question.exam), and its really a > student responding to it, not a student_exam. But if we used student_exam, > we could use response.student_exam.exam to get back to the exam, and > response.student_exam.student to get back to the student. > 3. If we were on an *Evaluation* and we wanted to back to a exam, it > would seem quite cumbersome to do evaluation.response.question.exam > just to get back to the exam. > - Now we could always create a method on the model that just > shortened it for us, but *is there a point when you are chaining > associations that somewhere along the line you add in another > foreign_key > to a table for easy lookup*? > 4. If we wanted to see all *Evaluations* for an *Exam*, what would be > the best way to do that? > - Only way I could see to do it easily would be to break it up, > something like: > - @questions = @exam.questions > - @responses = Response.where(question_id: @questions.pluck(:id) > - @evaluations = Evaluation.where(response_id: > @responses.pluck(:id) > - This seems kind of painful > > > Let me know your thoughts -- or if you have any great books on the best > strategies for normalizing/denormalizing within or without the scope of a > rails app, I'd love to hear them. > > > > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/cb91044d-20dc-444c-8172-a7b72bffd3a4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
