> In addition to other answers:
>
> - it has no NULLs, which are nasty
> - it should be easy to make it recursive
> - you can do full "bill of material"s with it ( didn't check though ;)

So a little review:
Alexandre: every record have two ids, 1. self ID and 2. Parent ID
Martijn: to have records table and separate Links table with Parent,
child relationships only

Am i right, please?