Re: Relationship Issue

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Pardon my ignorance for a moment.

I looked at this example that you pointed me to and have a question.
When I add a new item do I not have to modify every record in the
tree? That sounds like a lot of work. Granted I looked at my
original structure and decided that querying it would be quite
disgusting. But the question still exists.

Thanks,
Jason


On Feb 13, 7:13 am, "Jason Lepack" <jlep...@xxxxxxxxx> wrote:
Interesting... Good note Jamie.

Goes back and pulls out his University text on Foliage... I mean
trees.

Cheers,
Jason Lepack

On Feb 13, 5:36 am, "Jamie Collins" <jamiecoll...@xxxxxxxxxx> wrote:



On Feb 12, 4:49 pm, "Jason Lepack" <jlep...@xxxxxxxxx> wrote:

tbl_parts:
part_id - autonumber - pk
part_description - text

tbl_bom: (bill of material)
bom_id - autonumber - indexed(no dupes)
part_id - number - PK
sub_part_id - number - PK

Yes, your structure is denormalized. That's the nature of the
adjacency list approach :(

If you want a normalized model, try the nested sets approach. See:

Trees in SQL
by Joe Celkohttp://www.intelligententerprise.com/001020/celko.jhtml

His book, 'Trees and Hierarchies in SQL for Smarties' is pretty much
essential reading on the subject.

Jamie.

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