On Wednesday, January 13, 2016 at 2:22:51 AM UTC-5, Lei Zhang wrote: > > I am going to implement a small and simple search feature in my project. > But got a question about the scenario I have right now. So hope to get some > tips from here. > > First of all, this is a rails app. > > There are two models, A and C. > > A has_many C. > > That's to say, it might have some situation like this: > > A1 related to C1, C2, C3, C4 > A2 related to C2, C3, C4, C5 > A3 related to C2, C3, C4, C8 > A4 related to C3, C4, C8, C9 > A5 related to C4, C8, C9, C20 > > Use C2, C3, C4 as keyword, I can get A1, A2, A3 > Use C4, C8, C9 as keyword, I can get A4, A5 > > I consider that this can be done by using something straightforward like > A.Cs.includes?(C2,C3,C4). > > But that requires an iteration of A. And I concern that it would have some > performance issue. >
If you want to load matching As without instantiating the Cs, you could do something like: A.where(id: C.where(code: params[:codes]).pluck(:a_id)) If you are going to instantiate all As and Cs found anyway, you could just use eager loading: found_c = C.where(code: params[:codes]).includes(:a) found_a = found_c.collect(&:a).uniq Jim -- 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/6282f2d0-c074-417b-8f6f-f9c460a6714e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
