The following illustration shows the purchase order flow through the hub system.
Hub system initiates a business transaction
A business transaction is initiated when the ordering application generates a purchase order (PO) named PO.xml, and delivers it to the receivepo message queue, which is monitored by the Receive PO receive function. The document is submitted to a BizTalk Messaging Services channel configured for PO processing. The HubReceivePO messaging port activates a new instance of the XLANG schedule Hub.skx, and then delivers the document to the ReceivePO port on that XLANG schedule. The schedule contains some business logic to apply a simple approval process to the purchase order. For this scenario, the purchase order is automatically approved if the total value is less than $1,000.00. If the PO.xml document is approved, it is sent to the HubSendPO channel for further processing. When the processing completes and the correlation information is written to a database, the purchase order is sent to the supplier by means of an application integration component (AIC) that functions as a client to the supplier's XML Web service.
Notes If the PO.xml document is denied, the schedule terminates, and no further documents are processed for the business transaction.
The purchase order \Microsoft .NET Server Solutions for the Enterprise\E-Procurement\Application\PO.xml is used as a template document by the ordering application. This document is populated with a purchase order number and purchase order total when the user submits the order.