ORM podcast special

Everything you wanted to know about ORM but were afraid to ask. Who hasn’t come across names and abbreviations like ORM (Object To Relation Mapping), JPA (Java Persistence API) or Hibernate by now? In our next podcast episode we’ve put together 90 minutes devoted entirely to this subject. The topics are listed below. Two special guests joined us for the recording, Lukáš Křečan for Hibernate and Martin Krajčí for JPA.

Topics covered

• history and basic concepts
• the evolution from JDBC and SQL to ORM and OQL
• what ORM stands for
• the basic idea and why use ORM
• mapping
• relationship types and ways to represent an object graph in a relational model
• how mappings are written (annotations, XML)
• OQL, the query language for ORM
• the difference between SQL and OQL
• basic interactions
• API (session or entity manager)
• support inside and outside the J2EE stack
• the standardized option, JPA
• the basics
• the proprietary option, Hibernate
• the basics
• transactions
• JTA
• local transactions
• use in Java SE outside an application server
• comparing JPA and Hibernate
• standards age much faster, while Hibernate keeps evolving
• standards should be more portable
• Hibernate is tied to JBoss (Red Hat doesn’t have to invest in R&D)
• …
• solving common problems
• record locking (optimistic and pessimistic locking)
• HTTP challenges
• attaching and detaching objects
• access to uninitialized associations in the UI (Open Session in View)
• pros and cons of ORM
• learning curve
• available tools
• portability of JPA-based applications
• performance compared with plain SQL
• the N+1 problem
• second-level cache
• testability (unit and integration tests)