[TYPO3-semantic] Brain storming - what relation for storing a hierarchy?

[Fabien Udriot]

Hi,

My next priority is to focus on a functional triple store within TYPO3.

Use case
========

A user can define and organize "Concepts" within an hierarchy. A "Concept" is a abstract notion that 
is used to establish relations with other records. In my first implementation, the UI will 
represents this hierarchy in the form of a tree which is a well known widget in the TYPO3 Backend.

Implementation
==============

Semantically speaking, what would be the best relation to store this kind of hierarchy? I am 
thinking of a symmetric relation encompassing two relations (or predicates) for each node:

- "is_child"
- "is_parent"

For each triple created with relation "is_child", a relation "is_parent" would be created. This 
would facilitate to query the "tree" in the both direction. But maybe, it is superfluous as we can 
query the triple store in the other direction (AKA findSubjects() method - cf. next post)

What do you think of this approach?

In our last Skype meeting, Thomas suggested to come up with some interfaces. To avoid loading the 
post too much, I made a proposition in my next post.

Cheers,

Fabien