how to search one object and return another related object

Question

I am trying to create search form when user search for a course it returns list of user's names who are taking that course.So i have user table,course table and user-course join table.I want o use metasearch or ransack.But i wonder how i would use these in my case.Thank you in advance.

create_table "users", :force => true do |t|
  t.string   "firstname"
  t.string   "email"
  t.string   "encrypted_password",   :limit => 128, :default => "", :null => false
  t.string   "password_salt",                       :default => "", :null => false
end


create_table "courses", :force => true do |t|
  t.string   "name"
  t.datetime "created_at"
  t.datetime "updated_at"
  t.integer  "school_id",  :null => false
end

create_table "user_courses", :force => true do |t|
  t.integer "user_id",   :null => false
  t.integer "course_id", :null => false
  t.boolean "active",    :null => false
end

class User < ActiveRecord::Base
  has_many :user_courses
  has_many :courses, :through => :user_courses
  has_many :active_courses, :through => :user_courses, :source => :course, :conditions => {'user_courses.active' => true}
  has_many :taken_courses, :through => :user_courses, :source => :course, :conditions => {'user_courses.active' => false}
end

class UserCourse < ActiveRecord::Base
  belongs_to :user
  belongs_to :course
end

class Course < ActiveRecord::Base
  validates_presence_of :name
  has_many :user_courses
  belongs_to :school
end

Answer 1

You can add this to your Course model:

has_many :users, :through => :user_courses

Then you can get the users from a course like so

Course.find(1).users