In my model i have the following bit of code.
hash_values = JSON.parse(question_hash)
hash_values.each do |k,v|
b = UpdateData.new
b.question, b.answer, b.phase = v[0].to_i, v[1], v[2].to_i
b.save!
end
I have a problem of phase value. b.phase has an id of 0 to 5 and it also should be null. When the data is not entered for the phase the value is ""(.to_i = 0) it considered as 0 in database. I need to store an null value rather than 0 if phase value is "".
Just check if the string is empty:
if v[2].empty?
b.phase = nil
else
b.phase = v[2].to_i
end
or a nice one liner using a ternary operator:
p.phase = v[2].empty? ? nil : v[2].to_i
Try:
hash_values.each do |k,v|
b = UpdateData.new
b.question, b.answer = v[0].to_i, v[1]
b.phase = v[2].blank? ? nil : v[2].to_i
b.save!
end
blank? so that is one question mark, the other is due to the ternary operator (or 'inline if statement')
There is a gem that can do that for you automatically for every attributes existing in your model :
Add this to your Gemfile and run bundle install :
gem 'nilly_vanilly'
This gem will convert any empty string into a NIL value to be store into your DB.
====== UPDATE =====
I just tried this Gem and it is not working. I reported it, and the developper said there was an incompatibility with postgreSQL. He is patching the gem. In the time being, I end up with creating my own library.
Just create the file lib/my_model_tools.rb containing the following lines :
module MyModelTools
private
def blank_string_attributes_to_nil
self.attributes.each do |attr_name, attr_value|
self.send("#{attr_name}=", nil) if attr_value.kind_of?(String) && attr_value == ''
end
end
end
Then you have to add these lines into each of your app/models/* files :
require Rails.root.to_s + '/lib/my_model_tools.rb'
class MyExampleModel < ActiveRecord::Base
include MyModelTools
before_validation :blank_string_attributes_to_nil
...
end
This will convert any empty string attributes into a NIL value to be store into your DB (for the models where you copy the lines above).
So you won't have to assign each attribute by hand to NIL when they are empty string.
