search for: rails_conf

...e a Presentation model which belongs to the Conference model. We don''t want to create nameless Presentations, so we class Presentation < ActiveRecord::Base belongs_to :conference validates_presence_of :name, :on => :create end Now we have a conference instance called rails_conf. When we try to create a new nameless Presentation through the association collection: rails_conf.presentations.create() #=> #<Presentation:0x39c5678 @errors=#<ActiveRecord::Errors:0x39af868 @errors={"name"=>["can''t be blank"]}, @base=#<Presentation:0x39...