Question

If I have a legacy database where I the relationships between 2 entities are defined in a different table. How do I create that relationship in rails?

The basic relationship I want to present is:

—Admins:

First_name
Last_name
id

—Sites:

id
subject

—Admin_Sites

 id
 teacher_id
 class_id

I know in rails I would just use belongs_to: and has_many: but if I have a (constantly updated) teach_class table, I need to somehow specify that THAT’s where rails need to look for the relationship of who is related to which class. I am at a loss how I can specify this. Is it possible to somehow specify :foreign_key as “teach_class.teacher_id” in classes model?

Answer 1

see this blog for has_many :through relationship – http://ruby-on-rails-dipak-panchal.blogspot.in/2012/10/has-many-through-relationship.html

class Admin < ActiveRecord::Base
  has_many :admin_sites
  has_many :sites, :through => :admin_sites
end

class Site < ActiveRecord::Base
  has_many :admin_sites
  has_many :admins, :through => :admin_sites
end

class AdminSites < ActiveRecord::Base
  belongs_to :admin
  belongs_to :site
end