Marcin Rzeźnicki
2013-Apr-11 13:54 UTC
[ActiveRecord] Attribute aliasing is driving me nuts :-)
Hi folks! Quick question about alias_attribute in context of legacy database. I am on AR 3.2.11. I got very weird, but easy to follow, naming scheme to deal with. That is - every attribute is suffixed by ''_''. I thought I dealt with that cleverly, that is, I introduced common ''abstract'' base class for my models: class PersistentObject < ActiveRecord::Base self.abstract_class = true #... def self.define_attribute_methods super attribute_names.each do |old_name| next if old_name == primary_key if old_name == locking_column alias_attribute ''version'', old_name else new_name = old_name.chomp(''_'') new_name.downcase! alias_attribute new_name, old_name if new_name != old_name end end end end Basic things do work, I can refer to something called ''FLOWER_'' by model.flower, also some validators work correctly, eg. this one is fine: validates_length_of :name, :category, maximum: 255, allow_nil: true But, as always, not all that glitters is gold. Some things fail miserably eg. : validates_uniqueness_of :name, scope: :category throws weird errors about nil not responding to a method etc. That escaped my logic until I debugged what was really going on ( (I''ll get back to this later). You can fix that by using: validates_uniqueness_of :NAME_, scope: :CATEGORY_ Ugly, but works. Same things goes for dynamic finders. #find_by_name refuses to cooperate #find_by_NAME_ is fine. I read in various places about this problem and, honestly, didn''t like what I found out (euphemism for - I found that mightily stupid :-)). Then I started figuring this out by myself trying to judge what it takes to make at least unique validator work. After a bit of debugging I nailed that down to: #activerecord/validations/uniqueness.rb:56 #build_relation column = klass.columns_hash[attribute.to_s] Needles to say columns_hash cares nothing about my aliases and happily tries to procede with nil. Ok, so I modified my aliasing method to actually pack the stuff I needed into columns_hash, luckily at the point of aliasing columns''ve already been created so I could just put copies under respective new keys. That let me go past this issue but when I saw generated query I was stunned - it used wrong names in all the places. Madness. I gave up. So, my question is: maybe you know someone who has taken on this issue and released a solution? Or maybe there are plans to fix this on AR level? Or, the most welcome possibility, maybe this is dead simple to fix :-) I appreciate all the answers, thanks in advance. -- 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 rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/JUlt3NUoCsYJ. For more options, visit https://groups.google.com/groups/opt_out.