February 2004
Intermediate to advanced
848 pages
27h 25m
English
Content preview from WebLogic: The Definitive GuideBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Chapter 11. Using CMP and EJB QL
WebLogic’s EJB container supports container-managed EJB persistence based on the EJB 2.0 specification. When you deploy a CMP entity bean to WebLogic Server, the EJB container automatically handles updates to the EJB’s persistent fields by concurrent transactions, synchronizes its state with the underlying database table(s), and manages its relationships with other EJB instances.
WebLogic provides a number of enhancements to the standard CMP requirements. These can be divided into two basic categories: those that provide additional architectural options and make EJB development more convenient, and those that can be used to tune an EJB’s performance. In the first category, WebLogic lets you map container-managed fields to columns spread across multiple tables. During the development and prototyping stages, you can make WebLogic generate the necessary SQL tables for all entity beans and relationships defined in the EJB JAR. WebLogic does this by inspecting the information captured in the bean classes, as well as the abstract persistence schema and column mappings defined in the EJB deployment descriptors. In addition, you can ask WebLogic to validate the database schema expected by the EJB container at runtime.
WebLogic lets you defer certain tasks of the EJB container to the underlying database. For instance, if you’ve configured a remove operation on an entity bean to propagate to all related EJB instances, you can configure WebLogic so that it ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.