willy_metra wrote:

>>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?
>
>
>

One record with id,parent_id : simple,easy to implement (usualy simple
lookup on edit form)
Record with id as PK and separate linkage table one to many
(id,parent_id) : harder to implement, but gives more abilities : for
example each detail may have more than one parent (wheel can be included
in Jaguar and in Ford as detail) .Also this is more close to RDMS
theory :). But Be aware of circular deadlocks :).

Adomas