RE: POs considered harmful for dependent demands

[Bob Haugen <linkage@interaccess.com>]

Hartmut Hermes wrote:
> EDIFACT has some more specific message types which replace the use of purchase
> orders in many processes: DELFOR, DELJIT, HANMOV etc. 

Thanks, I know X12 has some similar message types.  Part of my point 
for core objects is that there is a core object buried inside each of those
alternative ways of expressing demands, whether they be EDIFACT or
X12 or whatever.  That core object is the same in each message, only
the add-ons are different.  One core object has properties like Resource,
Quantity, Timing, etc.  It may be contained in another object that adds
location and party-role information.  Around that core object would be
the authorization document, message type, etc.

> Indeed I am not sure which different process you name "dependent demands". 

"Dependent demand" is a relative concept.  That is, a dependent
demand is such because it is dependent on some other demand
or process.
For example:
* the components of manufactured products;
* the treatments required by a medical diagnosis;
* means of transportation to deliver an order;
* etc.

You could also extend the concept to reciprocal relationships
like payments, although I would use different terminology.

The core concept is dependency: because one event has occurred 
or one activity has been planned, other dependent events or activities 
necessarily follow.  And if the plan changes for the independent
activity, the dependents are inherently changed too, and "the system"
should know it.

> It would be helpful to have a process model identifying the parties and their activities.

I will be working with the BP group to get REA model documents
into the right place for ebXML; in the meantime, see previous REA 
messages, for links to REA papers.

Thanks for your interest,
Bob Haugen