Day 12. Developing Entity Beans Using Container-Managed Persistence

Over the past two days, you have completed your study of session beans, both stateful and stateless. Session beans are the first of three EJBs that you will come across. Yesterday you saw what a stateless session bean is and how it differs from a stateful session bean. You also covered the important concept of how to access EJBs via non-EJB clients, such as RMI and CORBA clients. At the end of the day, you used a session bean to finish building the model layer of the Airline Ticket Reservation System MVC application.

Today and tomorrow, you will discover the second EJB type: entity beans. You will start the day by looking at entity bean concepts, the life cycle of an entity bean, and a flowchart that will serve to develop an entity bean using container-managed persistence. Then you'll move on to the two ways persistence is handled in entity beans: through container managed persistence and bean-managed persistence. Finally, you'll take a look at the new EJB Query Language (EJB QL) as well as WebLogic Server's extension to the EJB Query Language called the WebLogic Query Language (WLQL).