Rails 3 build a select tag with has_many belongs_to association

Based on following models

class Company < ActiveRecord::Base
  belongs_to :country
end

class Country < ActiveRecord::Base
  has_many :companies
end

I want to have in my companies/_form a select tag containing a开发者_JS百科ll the countries

I think that the Company.new(params[:company]) in companies_controller#create can create the association between company and the selected country

I'm running rails 3.0.0, what is the best way to achieve that?

thanks for your insights

collection_select should do the trick for you:

collection_select(:company, :country_id, Country.all, :id, :name, :prompt => 'Please select country')

The above code assumes that the countries table have a name column. If it doesn't, replace the fifth parameter with whatever the column of the country name is.

:prompt means that you're forcing the user to choose one country.

Find more information in the Rails API documentation.