polymorphic-associations

I'm relatively new to Rails. I would like to add an association to a model that uses the polymorphic association, but returns only models of a particular type, e.g.: class Note < ActiveRecord::Base # The true polymorphic association belongs_to :subject, polymorphic: true # Same as subject but where subject_type is 'Volunteer' belongs_to :volunteer, source_association: :subject # Same as subject but where subject_type is 'Participation' belongs_to :participation, source_association: :subject end I've tried a vast array of combinations from reading about the associations on ApiDock but nothing

I'm slightly confused about a polymorphic association I've got. I need an Article model to have a header image, and many images, but I want to have a single Image model. To make matters even more confusing, the Image model is polymorphic (to allow other resources to have many images). I'm using this association in my Article model: class Article < ActiveRecord::Base has_one :header_image, :as => :imageable has_many :images, :as => :imageable end Is this possible? Thanks. Yep. That's totally possible. You might need to specify the class name for header_image , as it can't be inferred. Include

A Person can have many Events and each Event can have one polymorphic Eventable record. How do I specify the relationship between the Person and the Eventable record? Here are the models I have: class Event < ActiveRecord::Base belongs_to :person belongs_to :eventable, :polymorphic => true end class Meal < ActiveRecord::Base has_one :event, :as => eventable end class Workout < ActiveRecord::Base has_one :event, :as => eventable end The main question concerns the Person class: class Person < ActiveRecord::Base has_many :events has_many :eventables, :through => :events # is this correct??? end

I'm trying to add an Evaluation model to my Rails 4 app. I have made a model called evaluation.rb . It has: class Evaluation < ActiveRecord::Base belongs_to :evaluator, :polymorphic => true belongs_to :evaluatable, :polymorphic => true I have also made concerns for evaluator and evaluatable as: module Evaluator extend ActiveSupport::Concern included do has_many :given_evaluations, as: :evaluator, dependent: :destroy, class_name: 'Evaluation' end end module Evaluatable extend ActiveSupport::Concern included do has_many :received_evaluations, as: :evaluatable, dependent: :destroy, class_name:

I have a table Foo that has a polymorphic belongs_to association called bar . The foos table has the standard bar_id column. However, instead of a string-based bar_type column, I have an integer bar_type_id column. This column references the id column in the table bar_types . bar_types.name holds the name of the class that represents the class of the particular bar instance. Does Rails (ideally >=2.3.10) allow for this type of polymorphic association? We did it by overriding the association_class method in a new module and included it using the :extend option. Also created a integer to string