STI and subclassing twice

rubyonrails-talk
1

I'm trying using STI to implement a hiearchy similar to this:

script/generate scaffold name:string type:string

class Person < ActiveRecord::Base; end class Customer < Person; end class Employee < Person; end class Developer < Employee; end

I.e., there are two levels of inheritance (Developer < Employee < Person).

When creating a Customer, Rails understands it's a Person, but if I create a Developer, Rails 'tends to forget' it's an Employee. In other words:

$ script/console

Developer.create :name=>'Bob'

=> #<Developer id: 1, name: "Bob", type: "Developer", created_at: "2009-05-08 09:59:58", updated_at: "2009-05-08 09:59:58">

exit

$ script/console

Employee.find :all

=>

Person.find :all

=> [#<Developer id: 1, name: "Bob", type: "Developer", created_at: "2009-05-08 09:59:58", updated_at: "2009-05-08 09:59:58">]

Worst of all, if I change the order of the 'find' statements, things work:

$ script/console

Person.find :all

=> [#<Developer id: 1, name: "Bob", type: "Developer", created_at: "2009-05-08 09:59:58", updated_at: "2009-05-08 09:59:58">]

Employee.find :all

=> [#<Developer id: 1, name: "Bob", type: "Developer", created_at: "2009-05-08 09:59:58", updated_at: "2009-05-08 09:59:58">]

Maybe this has to do with some caching stuff... any ideas?

2

There's some funky stuff with STI that basically boils down to the fact that if a class hasn't been loaded yet rails doesn't know it exists (and so doesn't create the correct query). One way of doing things is to force these classes to be loaded, eg at the bottom of person.rb put

require_dependency 'customer' require_dependency 'employee' require_dependency 'developer'

or something like that.

Fred

3

Interesting... That makes everything work as expected! Thanks