Rails - Apr 2006 - How to get validates_presence_of worked in this situation?

Suppose:
class articles < ActiveRecord::Base
  has_many :assistarticles

  validates_presence_of :body
end

class assistarticles < ActiveRecord::Base
  belongs_to :article

  validates_presence_of :detail
end

In the submit form:
  <%= text_field ''article'', ''body''  %>
  <%= text_field ''assistarticle'',
''detail''  %>

The process logic will be done in article_controller
Now if the article.body field is empty,then validates_presence_of will 
work and return the error to let user re-enter the body content,but if 
the assistarticles.detail is empty,then no tips at all,and the 
accordingly record will not be stored,either.  How to let the latter 
validates_presence_of work?

Thanks
Charlie

-- 
Posted via http://www.ruby-forum.com/.