Otherwise, in the next column, we will examine Service Data Objects, and how EJBs (both entities and sessions) will play a role within a Service Oriented Architecture.

SDO provides the ability to track changes to data objects using a ChangeSummary, and the JDBC Data Mediator Service allows the specification of an OCC column to manage data collisions on updates.

However, at least one column of any table or view must be identified to the JDBC data mediator service as the "primary key."