Simple search for all Rails 3 ActiveRecord models on any string column(s)

simple_search.rb

class ActiveRecord::Base
  class << self
    def has_simple_search(*attrs)
      raise 'has_simple_search expects at least one attribute' if attrs.empty?
      instance_eval do # because this is ActiveRecord::Base, the class inherits this
        write_inheritable_attribute(:simple_search_fields, attrs.flatten)
        def simple_search(search_string)
          attrs = read_inheritable_attribute(:simple_search_fields)
          like_s = attrs.map{|f| "#{self.table_name}.#{f.to_s} REGEXP ?"}.join(' OR ')
          terms = search_string.split(' ').map{|s| Regexp.escape(s.strip)}
          where(Array.new(attrs.count, terms.join('|')).unshift(like_s))
        end
      end
    end
  end
end

Usage:
In your model class:
has_simple_search(:attribute1, :attribute2...)

To search:
Model.simple_search('search string')

This search has been superseded by searchable, available here: https://gist.github.com/jimworm/35833846e851afec31ab