Subject Re: [firebird-support] Re: Database tree-like structure
Author Adomas Urbanavicius
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 :).