Sams Teach Yourself BEA WebLogic Server 7.0 in 21 Days

Yesterday you studied the second type of EJB, entity beans. You started the day by covering the concepts of entity beans. After this, you learned about the life cycle of an entity bean and studied a flowchart for developing an entity bean. You learned how entity beans can interact with a database using container-managed persistence (CMP) and bean-managed persistence (BMP). You devoted the rest of the day to understanding the concepts of CMP and learning how to use it for entity beans.

As part of the study of CMP, you learned about the newly introduced EJB Query Language (EJB QL) and how to write and embed queries in EJB QL. In addition to this, you also covered the extensions to EJB QL, provided by WebLogic Server, named WL QL. Finally, to reinforce the concepts studied throughout the day, you added the database interaction functionality to the restaurant application, implemented as entity beans that used CMP.

Today you will learn about the second way in which entity beans can interact with a database using bean-managed persistence (BMP). You will learn about the concepts of BMP and how the different APIs in the entity bean's life cycle need to be modified for BMP. Next you will study an entirely new alternative for enabling Java objects to interact with a database using the newly introduced Java Data Object (JDO) specification. In addition to this, you will learn how to use the EJB to JSP integration tool for Enterprise JavaBeans. Then you will implement the entity bean in the restaurant application using BMP instead of CMP, which was covered yesterday. Finally, you will build the data logic part of the Model layer of the Airline Ticket Booking System MVC application using entity beans (CMP way).