gistfile1.rb

#
# This exists as a way to make active record use SQL literals in attributes when
# creating or updating records
#
module ActiveRecord
  module ConnectionAdapters
    class Column
      class Literal < ::String
        def quoted_id() self end
      end

      @@type_cast = instance_method :type_cast
      def type_cast( value )
        if Literal === value
          value
        else
          @@type_cast.bind( self ).call( value )
        end
      end
    end
  end

  class Base
    def Base.Literal(*args, &block)
      ::ActiveRecord::ConnectionAdapters::Column::Literal.new(*args, &block)
    end
  end

  def self.Literal(*args, &block)
    Base.Literal(*args, &block)
  end
end

require 'set'
module Ci
  module Extension
    module ActiveRecord
      module ClassMethods
        # force these columns to use DEFAULT on create
        def use_db_default_in_columns(*column_names)
          column_names.each { |c| db_default_columns << c }
        end

        def db_default_columns
          @db_default_columns ||= Set.new("created_time")
        end
      end
    end
  end
end

module ActiveRecord
  class Base
    before_create :force_default_where_necessary
    after_create :reload_if_default_forced

    # force the sql keyword DEFAULT into those columns where there must be a
    # default value, that is, columns with a default that are not nullable, those
    # should have the DEFAULT keyword set 
    def force_default_where_necessary
      @default_forced = false
      @attributes.each_pair do |name, value|
        unless value
          column = column_for_attribute(name)
          if self.class.db_default_columns.include?( column.name ) or
             (column.has_default? and !column.null) then
            send "#{name}=", ActiveRecord::Literal('DEFAULT')
            @default_forced = true
          end
        end
      end
    end

    # if a default was forced, then we have to load the value that was stored in
    # the db into the record, AR won't, it'll just leave it as 'DEFAULT' which
    # really won't help much.
    #
    def reload_if_default_forced
      if @default_forced then
        self.reload
      end
    end
  end
end