I wanna use model attribute in view Rails - ruby-on-rails

Question

I am trying to use attribute value in model but its not working..
I have three models:
models/resident.rb
class Resident < ActiveRecord::Base
belongs_to :hostel
has_one :user,dependent: :delete
end
models/user.rb
class User < ActiveRecord::Base
belongs_to:resident
end
models/hostel.rb
class Hostel < ActiveRecord::Base
has_many :residents
has_one :rate_card,dependent: :delete
end
Schema
Resident
create_table "residents", force: :cascade do |t|
t.string "room_number"
t.string "roll_number"
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "hostel_id"
end
User
create_table "users", force: :cascade do |t|
t.string "roll_number"
t.string "email"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "resident_id"
end
Hostel
create_table "hostels", force: :cascade do |t|
t.string "hostel"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
Now i want to use the hostel attribute value in users/show.html.erb
I am able to do this :
<%if #user.resident.roll_number=="101303110"%>
if the roll number is present then returning true..
but if is use :
<%if #user.resident.hostel=="J"%>
and if J is a hostel present in Hostel model then it is returning false.
But when we put<%#user.resident.hostel%> in show.html.erb then it is showing value J.
How should I use related models attributes in each other view?

Answer 1

Given your associations, #user.resident.hostel would load a hostel. But you want to compare the hostel string on the hostel. Therefore your comparison should be:
<% if #user.resident.hostel.hostel == 'J' %>
Explanation:
#user # returns your a user
#user.resident # follows `belongs_to :resident` and
# returns a resident
#user.resident.hostel # follows `belongs_to :hostel` on the resident and
# returns a hostel
#user.resident.hostel.hostel # returns the value store in the `hostel`
# column of that `hostel`
Btw. I would argue that chaining calls like that violates the Law of Demeter. But it is hard to suggest any alternative without having more insights into your app.