acts_as_list :scope with habtm

Hello,

I have a problem with a little more complex DB-schema.

My target are and sorted trees like this:
1 One
1.1 One.One
1.2 One.Two
2 Two

I use for it two models:
- top: This an item, with the name and position
- agenda: Collections of tops

class Agenda < ActiveRecord::Base
  has_and_belongs_to_many :tops
end

class Top < ActiveRecord::Base
  has_and_belongs_to_many :agendas
  acts_as_list :scope => :parent_id
  acts_as_tree :order => :position
end

Datebase tops:
id | parent_id | position | title
1 | 0 | 1 | One
2 | 0 | 2 | Two
3 | 1 | 1 | One.One
4 | 1 | 2 | One.Two

Looks like: http://www.valibuk.net/?p=42

Works fine.

But my problem: The tops-database include tops for all agendas. So a
second agenda need also a new top with parent_id=0 and position=1:
5 | 0 | 1 | New One
... but acts_as_list used (sadly) correctly parent_id=0 and position=3

Result:
  acts_as_list :scope => :parent_id + "correct agendas"

Which scope-option I need? Anyone can me help with the SQL-statement?

Or I must used acts_as_nested_set? Never used it. But there the same
problem with :scope and habtm-relationship, I think.

Thanks for help
  Martin

Martin schrieb:

I have a problem with a little more complex DB-schema.

Anybody an idea?