How to set default values in models? -- in Ruby on Rails 3.1

Question

In RoR 3.1, "validates" still doesn't have a way of setting default values in the models. Or is there? If not, what's the best way to set default values?

Answer 1

One approach would be to set the default in your migration. This will be a property that will get set to your database. You can read more here: http://api.rubyonrails.org/classes/ActiveRecord/Migration.html

The other approach is to set a before filter, something like before_save or before_create, and then check if the value on an attribute is nil, you can set it to something.

class Abc
   before_save :set_default

   protected

   def set_default
     self.xyz = "default" unless self.xyz
   end
end

Answer 2

migration are best for setting default value
write a migration to update column and set default value

        self.up do 
           update_column :table_name,:column_name,:default=>your default value
         end

Answer 3

This works well for me

class WorkLogEntry < ActiveRecord::Base 

  after_initialize do
    self.work_done_on ||= Time.zone.today
  end

  ...
end