SOA: Joining data across multiple services

Question

Imagine we have 2 services: Product and Order. Based on my understanding of SOA, I know that each service can have its own data store (a separate database, or a group of tables

Answer 1

SOA is just a buzz-phrase for deploying components behind web services. How many data stores you have is entirely up to you. In some cases it makes sense to have partitioned data behind individual components, and in other cases all the data lives behind one service, and in other cases many components that expose service interfaces connect to the same database via the database's connection protocol. Approach the problem by approaching the problem, not be imposing artificial constraints.