databse relations that goes into circels

[3sgte]

Hello Everybody,

My last visit was a while ago, but I'm back! :-)

I'm not a newbie, I am with ms access for quite some time now,
bit still, there is a thing that puzzles me quite a lot.



For this, I made a screenshot from Northwind sample database.

The thing is, if you look at the relations of the database,
that it seemingly is possible to make a 'loop' !
(see below)


I still cant figure out why this is designed as it is,
and I still wondering how it is possible that this will
work, without errors and/or conflicting data in tables.

If you take 'Inventory Transactions, there is a one-to-many
relation to table 'products'.
then, from table 'products' there is another one-to-many
relation to table 'purchase Order Details'

AND THEN....
There is a one-to-many relation, (back!) to the first table
'Inventory Transactions' !!!

How is it possible that this seems to work?

I don't get it !!
(maybe I am not smart enough haha)
--
Is there anybody, willing to give some hints,
or explanation, how this works??
--

I hope with new information, to make better
database designs, maybe there is more possible,
instead of using strait forward one-to-many relations.

Many thanks!!

Reinier
The Netherlands

[Welshgasman]

Which northwind is this?, as version 2 is out now.

FWIW I had multiple paths to one table in one of my dbs. It still worked.

[June7]

Just might have to be more careful when building queries and remove links that are not suitable for desired output.

[3sgte]

[QUOTE=Welshgasman;530558]Which northwind is this?, as version 2 is out now.

The version = northwind 2.4
---
I found this on internet, written by GPGeorge:

"It's a result of converting the source accdb to a template and back into a new accdb. We have found no way to preserve a layout in the relationship window. It all goes to mush. Our team is working on updates (no estimated ship date quite yet but we hope to be able to do so before the end of the year, if all goes well). Part of that is to include a more readable relationship diagram in the on-line documentation."