Rails ActiveRecord::Relation undefined method

Question

I have the a model hospitals :

class Hospital < ActiveRecord::Base
  attr_accessible  :beds, :fax_no, :hospital_name, :phone_no, :district_id, :institution_type_id, :location_id, :division_id, :block_id, :hospital_type_id, :IsAdministrativeLocation, :IsTribal, :latitude, :longitude

  belongs_to:district
  belongs_to:division
  belongs_to:institution_type  
  belongs_to:hospital_type
  belongs_to:block

  has_many:hospital_reports
  has_many:health_dept_locations
  has_many:sanctioned_posts
  has_many:postings
  has_many:vw_sanctioned_working_by_hospitals
end

The vw_sanctioned_working_by_hospitals is a view as follows

mysql> desc vw_sanctioned_working_by_hospital;
+--------------------+---------------+------+-----+---------+-------+
| Field              | Type          | Null | Key | Default | Extra |
+--------------------+---------------+------+-----+---------+-------+
| hospital_id        | int(11)       | NO   |     | 0       |       |
| hospital_name      | varchar(255)  | YES  |     | NULL    |       |
| class_1_sanctioned | decimal(32,0) | NO   |     | 0       |       |
| class_1_working    | bigint(21)    | NO   |     | 0       |       |
| class_1_vacant     | decimal(33,0) | NO   |     | 0       |       |
| class_2_sanctioned | decimal(32,0) | NO   |     | 0       |       |
| class_2_working    | bigint(21)    | NO   |     | 0       |       |
| class_2_vacant     | decimal(33,0) | NO   |     | 0       |       |
+--------------------+---------------+------+-----+---------+-------+

The vw_sanctioned_working_by_hospital model is as follows :

class VwSanctionedWorkingByHospital < ActiveRecord::Base
        self.table_name = 'vw_sanctioned_working_by_hospital'
 belongs_to:hospital
end

But im gettting the following error :

Showing /home/akash/hrmis/beauty4/app/views/hospitals/show.html.erb where line #11 raised:

undefined method `class_1_sanctioned' for #<ActiveRecord::Relation:0xb1e5bd0>
Extracted source (around line #11):

8: <div class="span4">
9: <dl class="dl-horizontal">
10:   <dt><strong>class_1_sanctioned:</strong></dt>
11:   <dd><%= @hospital.vw_sanctioned_working_by_hospitals.class_1_sanctioned %></dd>
12: 
13:   <dt><strong>Hospital Name:</strong></dt>
14:   <dd><%= @hospital.hospital_name %></dd>

Where am I going wrong ? I have read that a db view can be interpreted just like a read only table,then what is the problem ?

My associations are correct and everything seems fine but I'm still not able to render the class_1_sanctioned column.

Answer 1

You have a has_many relation:

has_many :vw_sanctioned_working_by_hospitals

This actually returns a relation and not a single object. You would need to either specify which object you want eg

@hospital.vw_sanctioned_working_by_hospitals.first.class_1_sanctioned
@hospital.vw_sanctioned_working_by_hospitals.last.class_1_sanctioned
@hospital.vw_sanctioned_working_by_hospitals[123].class_1_sanctioned

Or (much more likely this is what you want) you need to iterate over the relation:

<% @hospital.vw_sanctioned_working_by_hospitals.each do |vw_sanctioned| %>
  <%= vw_sanctioned.class_1_sanctioned %>
<% end %>