Frederick Cheung wrote: > On Oct 19, 10:08�am, Max Williams <rails-mailing-l...@andreas-s.net> > wrote: >> I just noticed this odd behaviour (in rails 2.2.2). � It looks like >> changing the type with update_attributes *doesn't* work (but returns >> true!), but changing the field and then saving it *does* work. �Here i >> have an STI situation where TeachingObject and LearningObject extend >> Resource. >> >> The bit where update_attributes returns true, yet seems to fail, is >> rather disconcerting. �Can anyone explain what's going on here? > > I believe that the type column is marked as a protected attribute or > something along those lines. > > Fred
ahhh, well that would explain it. It would also explain why update_attribute returns true - it just silently ignores the protected fields. It's a bit annoyin that the api doesn't mention this: to quote >>Single table inheritance >> >>Active Record allows inheritance by storing the name of the class in a column >>that by default is named "type" (can be changed by overwriting >>Base.inheritance_column). This means that an inheritance looking like this: >> >> class Company < ActiveRecord::Base; end >> class Firm < Company; end >> class Client < Company; end >> class PriorityClient < Client; end >> >>When you do Firm.create(:name => "37signals"), this record will be saved in >>the companies table with type = "Firm". You can then fetch this row again >>using Company.find(:first, "name = ‘37signals’") and it will return a Firm >>object. >> >>If you don‘t have a type column defined in your table, single-table >>inheritance won‘t be triggered. In that case, it‘ll work just like normal >>subclasses with no special magic for differentiating between them or >>reloading the right type with find. >> >>Note, all the attributes for all the cases are kept in the same table. Read >>more: www.martinfowler.com/eaaCatalog/singleTableInheritance.html unquote. anyway, thanks Fred. max -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ 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 rubyonrails-talk@googlegroups.com To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
