polymorphic problema

It appears that I have the models and migrations set up correctly.

In case anyone is wondering why i set it up like this I had it working
with just a contact model and this will save a bunch of coding changes
to my already working CRUD ajax inline contact form. I am adding a
contrator model so I would like to have a polymorphic setup so I can
differentiate the two types of people in the form.

I have a Person that is polymorphic, it will have a contact and
contractor type.

class Person < ActiveRecord::Base
  belongs_to :contactable, :polymorphic => true

class Contact < ActiveRecord::Base
  has_many :people, :as => :contactable

When I do:

person = Person.create(params[:person])
@contact = Contact.create(params[:contact])
person.contactable = @contact

It goes without an error but puts NIL in the contactable_type and
contactable_id columns.

Anyone have an idea why? I spent a couple hours with this earlier.

In case anyone is wondering here is the migration:

class CreatePeople < ActiveRecord::Migration
  def self.up
    create_table :people do |t|
      t.integer :company_id
      t.references :contactable, :polymorphic => true


  def self.down
    drop_table :people

Are you saving the person record after having assigned the
contactable ?


The Create method saves on creation does it not?

Here is my stand alone script i just tried, still putting NIL in the contactable columns: I even tried person.contactable.save to no avail.

RAILS_ENV = ‘development’

require File.dirname(FILE) + ‘/…/config/boot’
require File.dirname(FILE) + ‘/…/config/environment’

@contact = Contact.create(:name => ‘moo’)
person = Person.create(:company_id => ‘1’)
person.contactable = @contact

Ok, I was looking at the DB for the contactable.type and id. Why does it not show up there but when you query it is is there?

I did the example in rails recipe. I can retrieve the addressable_id
and type when I create itfrom the console, but when I go log out and
go back and try to retrieve them they give back NIL just like the DB
shows. Is the ID and TYPE supposed to show up in the DB? I am still
getting NIL for the polymorphic columns. Stumped...

Ok, I did a new method instead of create and then the last thing I did
was a save and it works. Anybody know why?

Because assignment of the new parent record to a child is not
immideately persisted. You need to call save to persist it in the

So this changes only the object in memory:
person.contactable = @contact

This updates the database:
person.contactable = @contact


I did that even with the “create” methid, no luck. I had to use the “new” method and save it for it to write to the db.