Select tag and Many to Many Relation in Rails 4.0

Question

In my project i have 2 models Employee.rb

class Employee < ActiveRecord::Base
  has_many :shop
  ..
  ..
  ..
end

and Shop.rb

class Shop < ActiveRecord::Base
  has_many :employees
  ..
  ..
  ..
end

I'm not sure whether this relation is right or not. The working should be like this. Employee got a foriegn key employeeID which is used in many tables.. If an employee has got more than 4 shops then 4 entries of the same employee will be in the employee table(employeeID will be same for all) and so on. Now my issue is I have a form which updates the employee details. Form is used to create as well as edit employee details. I want to put a select tag in this form which shows all the shops. On edit page the shops that belongs to the user should be preselected..

How to do this? Help

Answer 1

You should use the has_and_belongs_to_many association:

--

Has And Belongs To Many

This will mean creating a new table:

#employees_shops
employee_id | shop_id

You can then associate the two models using the has_and_belongs_to_many declaration:

#app/models/employee.rb
Class Employee < ActiveRecord::Base
    has_and_belongs_to_many :shops
end

#app/models/shop.rb
Class Shop < ActiveRecord::Base
    has_and_belongs_to_many :employees
end

This will allow you to call:

@shop.employees.each do |employee|
    employee.name
end