What type of relations to choose if I want to link 2 models with one

Question

I have model Message. It may be posted by either Person or Organization from my DB. I want to call update.contact, where contact is Organization or Person.

class Update < ActiveRecord::Base
has_one :contact

The decision I like to use is like

class Organization < ActiveRecord::Base
belongs_to :update, as: :contact

But this approach not available in Rails. Should I use polymorphic association? How to organize the architecture for this case?

Answer 1

It sounds like Organization and Person might be two different variants of a same entity (a customer, user, whatever). So, why not create a common parent model for the two of them? Such a parent wouldn't necessarily need a table, and you might just define common methods inside of it. Update is more of an action rather than an object, which could be applied to a Contact object (typically in its controller). For the Contact class, polymorphic association can be used. So you might have:

class Parent < ActiveRecord::Base

# stuff Person and Organization share

end

class Person < Parent

has_one :contact, as: :owner

# Person methods etc.

end

class Organization < Parent

has_one :contact, as: :owner

# Organization stuff

end

class Contact

belongs_to :owner, polymorphic: true

def update
#...
end

# other stuff for Contact

end

Then you can write lines like:

Person.first.contact.update

or whatever you need to do with your objects.

In case your Organization and Person don't differ too much, you could just create a table for the parent class, and add the has_one etc. in there.