show names instead of ids rails - ruby-on-rails

Question

Hello i created 2 tables (categories and employees),both are in a relationship and i want to show category_name(Categories table) in my employees index view instead of id's
****Here is my Categories Table******
class CreateCategories < ActiveRecord::Migration
def self.up
create_table :categories do |t|
t.string :category_name
end
end
def self.down
drop_table :categories
end
end
****Here is my Enployees Table******
class CreateEmployees < ActiveRecord::Migration
def self.up
create_table :employees do |t|
t.string :name
t.string :last_name
t.integer :categories_id
end
execute "ALTER TABLE employees ADD CONSTRAINT fk_employees_categories FOREIGN KEY (categories_id) REFERENCES categories (id)"
end
def self.down
drop_table :employees
end
end
****Here is my Employee controller******
class EmployeeController < ApplicationController
def index
#employees = Employee.all
end
end
****Here is my Category controller******
class CategoryController < ApplicationController
def index
#categories = Category.all
end
end
****Here is my Category Model******
class Category < ActiveRecord::Base
has_many :employees
end
****Here is my Employee Model******
class Employee < ActiveRecord::Base
belongs_to :category
end
****Here is Employee view*******
<table>
<tr>
<th>Employee</th>
<th>Last Name</th>
<th>Category</th>
</tr>
<% #employees.each do |e| %>
<tr>
<td><%=h e.name %></td>
<td><%=h e.last_name %></td>
<td><%=h e.categories_id %>
</td>
Here in e.categories_id i want to show categories_name that is from my categories table
<td>
<%= link_to ("View" ,:controller=>"employee",:action=>"show", :id=>e.id ) %>
</td>
<td>
<%= link_to ("Edit", :controller=>"employee",:action=>"edit",:id=>e.id ) %>
</td>
<td>
<%= link_to ( "Delete",:controller=>"employee",:action=>"destroy", :id=>e.id ,:confirm=>"sure?" %>
</td>
</tr>
<% end %>
</table>
Can someone help me with this problem please?

Answer 1

In your employee index views,
<td><%=employee.categories.category_name %>
instead of
<td><%=h e.categories_id %>

Answer 2

<%= h e.category.category_name %>
will do the trick.
Note that if you just do this, it will cause an SQL query to be executed for each row that you're displaying (known as the N+1 problem).
So in your controller, you'll have to change
#employees = Employee.all
to
#employees = Employee.find(:all, :include => [:category])
This will force eager loading, and reduce the number of queries to 2.
(As a side note, you really should have moved on to Rails 3 by now. Rails 4 is current. Each version offers a lot more features than the last.)

Answer 3

In Your employee controller add this
It means that get category_name to appear on your index view instead of ID.
#category= Category.all()
#category_list=[]
#category.each do |c|
#category_list << [c.category_name,c.id]
end
and then in your index views
<td><%=employee.categories.category_name %>

Answer 4

I know this is a late answer, but for anyone who is looking for an answer, here is how I accomplished this,
I have a table realties that has a one to many association with features table. I used the railscast method for multiple checkbox selection, so for each realty it has certain features. I wanted to show the features of each realty in its row in the index view. I had in the show view, features are shown like this,
#realty.feature_ids
where #realty in the controller is
#realty = Realty.find(params[:id])
however, in the index view the realty.feature_ids only showed numbers only not the names.
To work this out here is what I did in the index view:
<% #realties.each do |realty| %>
<td>
<% realty.feature_ids.each do |feature| %>
<%= Feature.find(feature).name %>
<% end %>
</td>
<% end %>
so for the above question, loop through the ids with each loop, this will give you the id number, find it in the Category model with the .name method. So I guess the solution for you would look like this:
<% #employees.each do |employee| %>
<td>
<% employee.category_ids.each do |category| %>
<%= Category.find(category).name %>
<% end %>
</td>
<% end %>
I hope this will benefit someone.