Question

I’m trying to figure out on how to trigger the before_validation for only one specific column as you can see below.

class PartType < ActiveRecord::Base
  before_validation :fix_quotation

  protected
    def fix_quotation
      self[:quotation] = quotation_before_type_cast.tr(' $, ' , '.' ) if attribute_names().include?("quotation")
    end
end

but the attribute_names seems not to be working in this case.

I have some other columns on this model and if I do any change on other columns this validation are trigging.

This validation is working fine with the “quotation” column but I don’t want that the validation trigger on modifying “title column for example.

NOTE: I’m using the gem called “on_the_spot” to edit column values “on the spot”

Answer 1

Here’s how your model should be defined:

class PartType < ActiveRecord::Base
  before_validation :fix_quotation, :if => :quotation_changed? #this is where the magic happens

  protected
  def fix_quotation
    self[:quotation] = quotation_before_type_cast.tr(' $, ' , '.' ) if attribute_names().include?("quotation")
  end
end