Summary

Today you began your study of the second type of EJBs, namely, entity beans. You started the day with a brief look at entity bean concepts, the life cycle of an entity bean, and a flowchart to develop an entity bean. After this you delved deep into today's primary focus area, CMP.

In CMP, you covered the concepts behind CMP. More importantly, you discovered the way one-to-one, one-to-many, and many-to-many relationships are handled in the new CMP model using CMR fields. You then looked at the newly added EJB Query Language (EJB QL), which is a simple standard language for writing queries for finder methods that need to query the database. After this, you looked at the extension to the EJB QL query language provided by WebLogic Server called the WebLogic Query Language (WLQL). Finally, you added an entity bean in the restaurant application that you have been working on for the past few days. You implemented the ItemBean entity bean that enabled the ChefBean session bean to interact with the item table in the database so that it could fetch information for cooking ordered items.

Tomorrow you will study the second way that an entity bean can implement persistence using BMP.