Storing Directory Hierarchy in a Key-Value Data store

Question

What is a clean/efficient method for storing the directory Hierarchy/tree in a Key-Value database (in my case MongoDB but any of them)?

For example a tree structure

Answer 1

I suggest storing a heap to the the id's of the data items. I think this is the best plan. If you need lots and lots of stuff any heap element could be an index to another heap.

eg

{ "id:xxx", "id:yyy", "sub-heap-id:zzz"....}

If this is not clear post a comment and I will explain more when I get home.