Rails variable returns two different values?

Question

For some weird reason an instance variable I have puts out two different values on two different occasions.

$ puts @project.to_yaml

gives:

  id: 3
  title: '123'
  created_at: 2014-04-07 23:54:18.253262000 Z
  updated_at: 2014-04-09 09:20:33.847246000 Z
  amount_donated: 50000

and

$ @project.amount_donated

gives:

nil

Explain this one to me because I'm terribly lost.

EDIT Project model

class Project < ActiveRecord::Base
  require 'date'

  attr_accessor(:amount_donated)
  before_save :convert_params

  def convert_params
    if amount_donated.present?
      value = amount_donated.to_s.split(',').join
      value = value.to_f * 100
      update_column(:amount_donated, value.to_i)
    end
  end
end

whats is @project? could you please add the Project.rb source code (if it is a model, as I'm guessing) — Enrique Fueyo
– Enrique Fueyo, Commented Apr 9, 2014 at 10:07
copy and paste error there one one thing that was behind it that doesn't matter pdf. i'll remove that from the edit — Alain Goldman
– Alain Goldman, Commented Apr 9, 2014 at 10:20

Magnuss · Accepted Answer · 2014-04-09 10:33:15Z

1

update_column(:amount_donated, value.to_i) shows that you have a column amount_donated, but attr_accessor :amount_donated shows that you have a virtual attribute. So which one is it?

I'd suggest removing attr_accessor :amount_donated

edit:

The attr_accessor :amount_donated does something like this:

class Project < ActiveRecord::Base
  require 'date'

  before_save :convert_params

  def amound_donated
    @amount_donated
  end

  def amound_donated=(value)
    @amount_donated = value
  end

  def convert_params
    if amount_donated.present?
      value = amount_donated.to_s.split(',').join
      value = value.to_f * 100
      update_column(:amount_donated, value.to_i)
    end
  end
end

Thus when you accessed @project.amount_donated you were actually accessing the getter method amount_donated not the column (ActiveRecord getter).

Seems that to_yaml saw the column instead of the ActiveRecord's getter.

edited Apr 9, 2014 at 10:33

answered Apr 9, 2014 at 10:21

Magnuss

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1 Comment

Stefan Over a year ago

attr_accessor creates new getter and setter methods, overwriting AciveRecord's default getters and setters

Paritosh Piplewar · Accepted Answer · 2014-04-09 10:12:18Z

0

Try this, might be you are using cached copy of @project

@project.reload.amount_donated

answered Apr 9, 2014 at 10:12

Paritosh Piplewar

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