Rails - Jun 2005 - sorting on a habtm relationship

I have two tables ("products" and "categories") that have a
has_and_belongs_to_many relationship, and I need to be able to
arbitrarily sort products in the scope of a category using something
like acts_as_list.  Problem is, since each product can belong to
multiple categories, it doesn''t work to use acts_as_list and have the
"position" field be in the products table -- I would need to figure
out some way to put the position field in the categories_products
table.

Is there a non-messy way to do this?  Right now, I''m thinking about
just defining a categories_products model that belongs_to :product,
belongs_to :category, and acts_as_list.  That exposes some ugly
implementation details to the controllers, but I can''t think of
anything better.

Tyler

Tyler Kiley <tyler.kiley-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:
> Is there a non-messy way to do this?  Right now, I''m thinking
about
> just defining a categories_products model that belongs_to :product,
> belongs_to :category, and acts_as_list.  That exposes some ugly
> implementation details to the controllers, but I can''t think of
> anything better.
I''m not sure there''s any fancy handlers to help with this, but
you can
put the position on the categories_products table and it will show up
as an attribute:

category = Category.find(:first)
category.products.find(:first).position

You have to do some fancy foot work to update a join table attribute
though.  Take a look at the docs on habtm for more details on join
table attributes.
-- 
doug-jGAhs73c5XxeoWH0uzbU5w@public.gmane.org