Question

I have a method in my country.rb where I defined a new method.

class Country < ActiveRecord::Base
  has_many :states, :dependent => :destroy

  after_save :count_total_states

  def count_total_states
    self.duration = State.count(:conditions => { :country_id => self.id })
    Country.save!(:duration => self.duration)
  end
end

I got the self.duration result I wanted. But when I ran it, it said

undefined method 'save!' for #<Class:0x111170d10>

I want it to count number of states belong to the country everytime a new state is created. Please advise what to do. Thanks.

Answer 1

Just use update_column instead. It skips the callbacks and validations. Here are the docs on update_column.

Also, states.count already gives you the query to find the states by country. The has_many :states allows you to do this.

class Country < ActiveRecord::Base
  has_many :states, :dependent => :destroy

  after_save :count_total_states

  def count_total_states
    update_column(:duration, states.count)
  end
end