activerecord - Rails 3 polymorphic association with foreign_type column as integer -

we have problem polymorphic relation in rails/activerecord. mentioned in other question . reason need kind of polymorphic relation integer foreign_type column number of records in table, have 40 million record in table number raising. try save storage @ database server memory consumption concerning index handling @ database.

the question mentioned earlier related rails 2 , if tried uses rails 3 doesn't work. method of module never called , can't see why.

i have mapping column types see in migration class

class notification < activerecord::base   belongs_to :notifiable, :polymorphic => true end 

class user < activerecord::base   attr_accessible :name   has_many :notifications, :as => :notifiable end 

class comment < activerecord::base   attr_accessible :text   has_many :notifications, :as => :notifiable end 

class message < activerecord::base   attr_accessible :title, :text   has_many :notifications, :as => :notifiable end 

class activity < activerecord::base   attr_accessible :title, :description   has_many :notifications, :as => :notifiable end 

class createnotification < activerecord::migration   def change     create_table :notifications |t|       t.integer :notifiable_id       t.integer  :notifiable_type # should tinyint @ database       t.timestamps     end   end end 

i map comment , user numeric value , save numeric value instead of class name type information.

to make polymorphic belongs_to working, can that:

in config/initializers directory, create file , put theses lines:

module activerecord   # = active record belongs polymorphic association   module associations     class belongstopolymorphicassociation < belongstoassociation #:nodoc:       def klass         type = owner.send(reflection.foreign_type)         type.presence && type.constantize       end     end   end end 

then in each model, override notifiable_type (define hash constant , put anywhere like):

def notifiable_type   { 0: 'user', 1: 'comment', 3: 'message' }[read_attribute(:notifiable_type)] end 

and has_many, try (set int_class_type each model):

has_many :notifications, :conditions => ["`notifiable_type` = ?", int_class_type], :foreign_key => 'notifiable_id'