description for REA diagram

[Bob Haugen <linkage@interaccess.com>]

The description below applies to the REA diagram sent to this list
earlier today.  

Always open to suggestions for improvement.

-Bob Haugen

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Figure nn.nn provides an overview of the REA economic elements in
a typical product-oriented Order-Fulfillment Business Process.

The Business Process is composed of several Business Collaborations,
taken directly from the Catalog of Common Business Processes
(please insert correct reference).  The REA elements help to tie
all the components of the business process into one unified story,
with a beginning and a middle and an end.

* Query Product Information receives Product Master or Catalog information
  about the products that can be ordered.  In REA, products are 
  Economic Resource Types.

* Distribute Inventory Report receives information about products that
  are currently available.  This purpose could also be accomplished
  through a Query Availability process.  In REA, inventory is an
  Economic Resource.  Each inventory element is typed by a 
  Product Master (Economic Resource Type).  

* Create Order forms a Purchase Order (an Economic Contract) 
  composed of Line Items (Economic Commitments).  Each Line
  Item reserves the committed quantity of the ordered product type,
  due at the commited date and time.

* Notify of Shipment results in a Shipment (an Economic Event)
  which should fulfill one or more of the Purchase Order Line Items.

* Process Payment results in a Payment (an Economic Event)
  which pays for the Shipment (the REA "duality" relationship).

When all of the Line Items have been fulfilled, and all of the
Shipments have been paid for, the Business Process is complete.

Otherwise - if something goes wrong, and the shipments do not
fulfill the commitments, and the payments do not compensate
for the shipments, or some economic event is late or otherwise
incorrect - the problem can be expressed using the REA concepts
and relationships explained above.  

The above concepts and relationships are specified in the TMWG
UMM (please insert correct reference), but there is no programmatic
support for them in the first version of the ebXML Business Process
Specification Schema.  They could, however, be implemented in
business collaboration management software based on UMM.