For example a list and a sublist can have many items through a model called list_items.
Here are the models
class List < ActiveRecord::Base
has_many :sublists
has_many :list_items
has_many :items, through: :list_items
end
class Sublist < ActiveRecord::Base
belongs_to :list
has_many :list_items
has_many :items, through: :list_items
end
class Item < ActiveRecord::Base
has_many :list_items
has_many :lists,through: :list_items
has_many :sublists, through: :list_items
end
class ListItem < ActiveRecord::Base
belongs_to :list
belongs_to :sublist
belongs_to :item
end
This below is what i am trying to accomplish.
Items Library Page
Item 1
Item 2
Item 3
Item 4
Item 5
Lists Page
=============================
=List 1 =
=============================
=Item 2 =
=Item 4 =
=Sublist Start =
=Item 5 =
=Item 1 =
=Item 3 =
=============================
So an item without a sublist (like item 2 and item 4) would have the following fields populated in the List_Item Model
List_id = 1
Sublist_id = nil
Item_id = 1
An item with a sublist (like item 5 and item 1 and item 3) would have the following fields populated in the List_Item Model
List_id = 1
Sublist_id = 1
Item_id = 1
The reason i would like to do it this way is so i can do drag and drop by dragging to the sublist it will populate the sublist_id and by dragging out of the sublist the sublist_id will then be nil.
Would this be possible or is there a better way to do this this?
To answer your question: Yes, that's possible:
class A
has_many :bs
has_many :cs, through: :bs
has_many :ds, through: :cs
end
class B
has_many :cs
belongs_to :a
end
class C
has_many :ds
belongs_to :b
end
class D
belongs_to :c
end
If th association on A is named differently than the association on B, you need to supply the source
parameter to the through
-relation, like this:
class A
has_many :bs
has_many :cs, through: :bs, source: :ccs
end
class B
has_many :cs, as: :ccs
belongs_to :a
end
class C
belongs_to :b
end
This will allow you to:
A.find(1).bs # => collection of B-instances
A.find(1).cs # => collection of C-instances
I'm not sure, if this answers your question. I hope so, but I'm a little confused about your example, so if not, please do comment :)