self referential model?

rubyonrails-talk
1

is it possible to have a model be belong to itself?

say i have a category, and the category can be a subcategory of another category (or it might be a parent category)..

is this possible, and does it make sense?

something like:

class Category < ActiveRecord::Base    has_many: categories end

i kinda think it would make more sense to use a subcategory model.. but the system i am deriving from (which was written in php) is combining the models..

thanks!

2

Sergio Ruiz wrote:

is it possible to have a model be belong to itself?

say i have a category, and the category can be a subcategory of another category (or it might be a parent category)..

is this possible, and does it make sense?

Yes, it makes sense.

something like:

class Category < ActiveRecord::Base    has_many: categories end

i kinda think it would make more sense to use a subcategory model.. but the system i am deriving from (which was written in php) is combining the models..

No. As you'll see from the above plugin using one model does make more sense.

3

you can read rails guides.

class Employee < ActiveRecord::Base   has_many :subordinates, :class_name => "Employee", :foreign_key => "manager_id"   belongs_to :manager, :class_name => "Employee" end

With this setup, you can retrieve @employee.subordinates and @employee.manager.