Heterogenous FK column / multiple ancestries on same model

[kalsan]

Hi! This gem looks super interesting but I've got quite a weird use case and I was wondering if there is a way to achieve this with Ancestry.

Imagine two classes, Node and Category:

• Node has belongs_to: :parent, class_name: 'Node' and belongs_to: :category
• Category has belongs_to: :parent, class_name: 'Category'

So we can build hierarchies like:

• A: node112 -> .parent == node11 -> .parent == node1 (which would be ancestry on the parent_id attribute)
• B: but also node112 -> .category == category12 -> .parent == category1 (where we first go over the the category_id and then parent_id)

Ancestry paths would look something like:

• A: node1/node11/node112
• B: category1/category12/node112

So the classes would contain something like:

class Node
  has_ancestry ancestry_column: :parent_id, class: Node # option :class is a fantasy construct here
  has_ancestry ancestry_column: :category_id, class: Category
end

class Category
  has_ancestry ancestry_column: :parent_id, class: Category
end

However for Node this would likely be a problem since ancestry (if I anderstand correctly) would not know that node.parent should go on the parent_id ancestry while node.category would take once the category_id and then the parent_id.

Do I understand correctly that such a structure is currently not possible with ancestry?

Cheers!
Kalsan

[kbrock]

closure trees work much better for going across class boundaries.
If you want to use ancestry, STI has worked for many people.

In my main code base, we have created a level of indirection to bridge that gap, but that causes all sorts of nuances that severely impact performance. So I'm in the process of removing those where possible.

Related, or possibly unrelated: people have wanted to have multiple trees per node, but this into in the short term cards.

[kalsan]

Thanks, that answers my question.