Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

Rails how to update a column after saving?

I want to create an after_save method for my rate action. It would divide rating_score/ratings and update the column rating.

class KonkurrancersController < ApplicationController
  def rate
    @konkurrancer = Konkurrancer.find(params[:id])
    @container = "Konkurrancer"[email protected]_s

    @konkurrancer.rating_score += params[:vind][:rating].to_i
    @konkurrancer.ratings += 1
    @konkurrancer.save

    respond_to do |format|
      format.js
    end
  end
end

This is my model:

class Konkurrancer < ActiveRecord::Base
  after_save :do_foobar

  private
    def do_foobar

      rating_score = self.rating_score
      ratings = self.ratings
      rating = (rating_score/ratings)
      self.update_attributes(:rating => rating)

    end
end

My rails log:

Started POST "/konkurrancers/rate/46" for 127.0.0.1 at 2011-04-26 23:40:56 +0200

  Processing by KonkurrancersController#rate as */*
  Parameters: {"utf8"=>"Ô£ô", "authenticity_token"=>"MACFM37hX4S6XA9vryn7gtfl21P
vcaPBSiKDI8mfurg=", "vind"=>{"rating"=>"4"}, "id"=>"46"}
  ←[1m←[36mKonkurrancer Load (1.0ms)←[0m  ←[1mSELECT `konkurrancers`.* FROM `kon
kurrancers`←[0m
  ←[1m←[35mCACHE (0.0ms)←[0m  SELECT `konkurrancers`.* FROM `konkurrancers`
  ←[1m←[36mCACHE (0.0ms)←[0m  ←[1mSELECT `konkurrancers`.* FROM `konkurrancers`←
[0m
  ←[1m←[35mKonkurrancer Load (1.0ms)←[0m  SELECT `konkurrancers`.* FROM `konkurr
ancers` WHERE (`konkurrancers`.`cached_slug` = '46') LIMIT 1
  ←[1m←[36mSQL (2.0ms)←[0m  ←[1mSELECT sluggable_id FROM slugs WHERE ((slugs.slu
ggable_type = 'Konkurrancer' AND slugs.name = '46' AND slugs.sequence = 1))←[0m
  ←[1m←[35mKonkurrancer Load (1.0ms)←[0m  SELECT `konkurrancers`.* FROM `konkurr
ancers` WHERE (`konkurrancers`.`id` = 46) LIMIT 1
  ←[1m←[36mSQL (0.0ms)←[0m  ←[1mBEGIN←[0m
  ←[1m←[35mLink Load (1.0ms)←[0m  SELECT `links`.* FROM `links` WHERE (`links`.k
onkurrancer_id = 46) LIMIT 1
  ←[1m←[36mSQL (0.0ms)←[0m  ←[1mROLLBACK←[0m
Rendered konkurrancers/_rating.html.erb (1.0ms)
Rendered konkurrancers/rate.js.erb (22.0ms)
Completed 200 OK in 606ms (Views: 286.0ms | ActiveRecord: 6.0ms)

How should I create this?

like image 610
Rails beginner Avatar asked Apr 25 '11 09:04

Rails beginner


People also ask

What does persisted mean in rails?

Persisted means the object has been saved in the database. You can only call it on ActiveRecord objects.

What does SAVE do in Ruby on Rails?

save is an “Instance Method”, it returns either true or false depending on whether the object was saved successfully to the database or not. If the model is new, a record gets created in the database, otherwise the existing record gets updated.

Does Rails create save?

If successfully validated, Create method creates an object (or multiple objects) and saves it to the database. The resulting object is returned whether the object was saved successfully to the database or not. From the above example, you can know that Create is a class method.


1 Answers

Any update_attribute in an after_save callback will cause recursion, in Rails3+. What should be done is:

after_save :updater
# Awesome Ruby code
# ...
# ...

private

  def updater
    self.update_column(:column_name, new_value) # This will skip validation gracefully.
  end
like image 115
zakelfassi Avatar answered Sep 20 '22 21:09

zakelfassi