To demonstrate how the <assign> activity can be used to manipulate larger sets of data, we will create an additional BPEL process, called AnotherBookstoreBPEL. This bookstore will return the book stock quantity, similar to the other two bookstores. The only difference will be that it will use a different XML Schema; hence, we will need to map the data elements from one schema to another for the invocation and back (for the response). Using a different schema will demonstrate a scenario that is very common in real-world cases, where services use different schemas; therefore, we need to do mappings and transformations.

For the AnotherBookstoreBPEL process, we will use the following schema:

We can see that the BookData element differs considerably from the BookData element of the BookstoreABPEL and BookstoreBBPEL processes. Also, the response from AnotherBookstoreBPEL is StockQuantity of the type int.