Ruby on Rails: before_save fields to lowercase

Question

I'm trying to change the fields from the form to lower case before they get saved in the database. This is my code but the output from the database is still in upper case why isnt the code working?

class Transaction < ActiveRecord::Base
   validates :name, presence: true
   validates :amount, presence: true, numericality: true
   before_save :downcase_fields

   def downcase_fields
      self.name.downcase
   end
end

Answer 1

downcase returns a copy of the string, doesn't modify the string itself. Use downcase! instead:

def downcase_fields
  self.name.downcase!
end

See documentation for more details.

Answer 2

You're not setting name to downcase by running self.name.downcase, because #downcase does not modify the string, it returns it. You should use the bang downcase method

self.name.downcase!

However, there's another way I like to do it in the model:

before_save { name.downcase! }

Answer 3

String#downcase does not mutate the string, it simply returns a modified copy of that string. As others said, you could use the downcase! method.

def downcase_fields
  name.downcase!
end

However, if you wanted to stick with the downcase method, then you could do the following:

def downcase_fields
  self.name = name.downcase
end

This reassigns the name instance variable to the result of calling downcase on the original value of name.