Callback Problem: Why to use self.var= instead of @var=

rubyonrails-talk
#1

Hi,

I've defined the following model:

class Eintrag < ActiveRecord::Base
  before_validation :vali

  protected
  def vali
  # self.feld1.reverse!
    self.feld2 = self.feld1
  end
end

Now I'm wondering why I have to write
self.feld2=self.feld1
and why
@feld2=@feld1
doesn't work.

I've found the thread
http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/3405e38a2f34e896/7cfa3cb86d87d034?lnk=gst&q=callback+self+instance#7cfa3cb86d87d034
But it's missing the reason.

Thanks,
martin

#2

Because activerecord attributes aren't stored as instance variables.

Fred