Issue with associations

[Shpigford]

I have a categories table that has parent categories and sub categories that are attached via "parent_id"

I then have items that are attached to the specific category via "category_id".

My associations:
Item belongs_to Category
Category has_many Items

The item really always has a category_id that matches one of the sub categories but there are places where I need to get parent category as well.

So my question is how can I get the parent category?

Right now if I want the sub category I just do item.category.title (which works because of my association)...but I want to be able to do something like item.category.parent_id.title so I can get the title of the main parent category.

Any ideas?

[thebasti]

What you need is a self referential category model. You probably want something like this in your category model:

belongs_to :parent, :class_name => "category", :foreign_key => "parent_id"
has_many :sub_categories, :class_name => "category", :foreign_key => "parent_id"

Once you have that you'll be able to do:

item.category.parent.title