Hi, I''ve a Category model with fields: *id *name *project_id and class defition: _______________________________________________________________________________ class Category < ActiveRecord::Base belongs_to :project has_many :choices has_many :voices, :through => :choices validates_presence_of :project_id, :message => "Selezionare un progetto." end _______________________________________________________________________________ the other model is Project with fields: *id *name *project_type_id and class definition _______________________________________________________________________________ class Project < ActiveRecord::Base has_many :voices, :order => :name has_many :categories, :order => :name belongs_to :project_type validates_presence_of :name validates_presence_of :project_type_id def project_type ProjectType.find(project_type_id).name if project_type_id end end _______________________________________________________________________________ What I want is the ability to block category duplication but only when project_type_id of the project is 2. I thought I could write something like this in the Category model: validates_uniqueness_of :name, :scope => :project_id if Project.find_by_id(3).project_type_id == 2 which indeed works but how can I make dynamic using the project_id of the current category? I mean I would like to replace ...find_by_id(3).... with something like ....find_by_id(project_id).... As an alternative I''ve tried also defining a validate method in the Category model but without luck, it always validates or invalidates the insertions. Thank you. Nik P.s. I''m just learning RoR and OOP so excuse my coding. -- Posted via http://www.ruby-forum.com/. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk-unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---