polymorphic-associations

I'm trying to create a relationship between addresses and trips, and I'm not sure exactly how to set up the relationship. Each trip will have two addresses: the starting address and the ending address. Addresses can be used in many different trips, and they can either be the starting address or the ending address depending on the trip. What I envision is that when users are creating a new trip, they can select from a dropdown of all their addresses, so they could make a trip from their address called, say, "home" to their address called, say, "airport." There is already a polymorphic

Sorry for the title, it's difficult to explain. I need a data model similar to this: As you can see, a set can belong to both a user or a school. My problem: It should only be allowed to belong either to a user OR a school. But never both at the same time. How can I solve this problem? Your current design is called exclusive arcs where the sets table has two foreign keys, and needs exactly one of them to be non-null. This is one way to implement polymorphic associations, since a given foreign key can reference only one target table. Another solution is to make a common "supertable" that both

class Transaction < ActiveRecord::Base belongs_to :account, :polymorphic => true end class Bankaccount < ActiveRecord::Base has_many :transactions, :as => :account end class Creditcard < ActiveRecord::Base has_many :transactions, :as => :account end Trying to do a summation of transactions where the account is active. Transaction.sum(:all, :conditions => "account.status = 'active'", :include => :account) So after some reading I came across this: The reason is that the parent model‘s type is a column value so its corresponding table name cannot be put in the FROM/JOIN clauses of that query. The

Using Ruby on Rails, how can I achieve a polymorphic has_many relationship where the owner is always of a known but the items in the association will be of some polymorphic (but homogenous) type, specified by a column in the owner? For example, suppose the Producer class has_many products but producer instances might actually have many Bicycles, or Popsicles, or Shoelaces. I can easily have each product class (Bicycle, Popsicle, etc.) have a belongs_to relationship to a Producer but given a producer instance how can I get the collection of products if they are of varying types (per producer

I want to make polymorphic associations with paperclip, and allow my user to have one avatar and multiple images. Attachment model: class Attachment < ActiveRecord::Base belongs_to :attachable, :polymorphic => true end class Avatar < Attachment has_attached_file :image, :styles => { :thumb => "150x150>", :view => "260x180>" }, end class Image < Attachment has_attached_file :image, :styles => { :thumb => "150x150>", :view => "260x180>" }, end User Model: has_one :avatar, :as => :attachable, :class_name => 'Attachment', :conditions => {:type => 'avatar'} accepts_nested_attributes_for :avatar

I have a User model, which belongs to Profile (belongs_to polymorphic). One model comes in two subclasses, but the profile_type in User always correspond to the parent model. User < ActiveRecord::Base belongs_to :profile, :polymorphic => true SomeProf < ActiveRecord::Base has_one :user, :as => :profile SomeDeepProf1 < SomeProf SomeDeepProf2 < SomeProf Then: sdp1 = SomeDeepProf1.new user = sdp1.create_user user.profile_type > 'SomeProf' Even stating the association in subclasses, the profile_type remains SomeProf . Why does this happen? Is there any way profile_type match subclass and not the