I was wondering if anybody knows an easy way to pass a method name as the scope option to a validates_uniqueness_of validation on a AR model?
For example, I have nested models a bit like:
class Survey has_many :areas end
class Area belongs_to :survey has_many :questions, :order => 'position' validates_uniqueness_of :position, :scope => : survey_id end
class Question belongs_to :area validates_uniqueness_of :position, :scope => : area_id end
So to get the questions on a survey, sorted by the 'survey_position' attribute I have to add a foreign key to the question, so that I can pass the survey_id to the :scope argument on validates_uniquess_of. So, I have to add this stuff to Survey and Question classes:
class Survey has_many :questions, :order => 'questions.survey_position' end
class Question belongs_to :survey validates_uniqueness_of :survey_position, :scope => :survey_id end
This creates problems for when saves cascade down associated objects.
Any ideas on how to pass a method name as the scope option? Then I could add (instead of the above):
class Survey def questions find_all_questions.sort_by(:survey_position) end end
class Question validates_uniqueness_of :survey_position, :scope => :survey_id_from_area
def survey_id_from_area area.survey.id end end
Any ideas?
~ Mark