Question

Suppose I am entering validation code into my model of multi-language publication database. The database needs either an English or a Japanese title for a particular journal. So I need to validate_presence_of at least one of the two. Right now I can easily check that both exists, but am stumped on the case of ‘at least one’:

class Article < ActiveRecord::Base   belongs_to :publication   validate_presence_of :journal_title   validate_presence_of :journal_title_ja end 

I think this might require a statement like:

:if => :jornal_title_ja is nil 

Answer 1

class Article < ActiveRecord::Base     belongs_to :publication     validate_presence_of :journal_title, :if => :check_japanese     validate_presence_of :journal_title_ja, :if => :check_english    def check_japanese     journal_title_ja.nil?   end    def check_english     journal_title.nil?   end end 

This should work. Hope I got the question straight.

Watch the episode no. 41 on railscasts for better understanding