[ACCEPTED]-Rails how to update a column after saving?-ruby-on-rails-3
Any update_attribute in an after_save callback will cause recursion, in 1 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
Not sure why people are upvoting the wrong 7 answer and downvoting the correct answer.
Zakelfassi 6 is right and Christian Fazzini is wrong 5 for Rails 3 and above. If you do #update_attributes 4 in a save callback you go into an endless 3 recursion. You want to do #update_column 2 as per his example.
Try it for yourself and 1 you'll see.
what you want is a callback. You can create 7 an after_save callback on your Konkurrancer 6 model, which triggers after the save() method 5 is called for that model.
For example:
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(:ratings => rating)
end
end
[EDIT] You 4 should use self, since the model you are editing 3 is the model itself. Test it out, and apply 2 necessary logic/implementation.
Have a look 1 at this guide for more info.
Hope that helps!
@konkurrancer.update_attributes :ratings=>'updated value'
0
Many of the answers on this post might have 7 been correct but are out of date now. The 6 Rails docs suggests assigning values directly (self.attribute = 'value') instead 5 of updating or saving attributes (update(attribute: 'value') in callbacks.
Good
after_save :do_foobar
private
def do_foobar
self.attribute = "value"
end
Bad (.update_column)
Safe 4 because it will prevent additional callbacks 3 from being triggered but not suggested as 2 it can have unintended side effects.
after_save :do_foobar
private
def do_foobar
update_column(:attribute, "value")
end
Worse (.update)
Can 1 trigger subsequent callbacks infinitely.
after_save :do_foobar
private
def do_foobar
update(attribute: "value")
end
More Related questions
We use cookies to improve the performance of the site. By staying on our site, you agree to the terms of use of cookies.