Posted in: Java Persistence API,JPA
What is JPA ? - JPA is the Java Persistence API, the entity persistence model for EJB 3.0
- Standardized persistence framework which is implemented by Hibernate (or TopLink, Cayenne, etc.)
- JPA Annotations and persistence.xml provide vendor independent configuration
- EntityManager provides vendor independent access to persistence
- Replaces vendor specific query languages (HQL) with standard (JPQL)
Why JPA ?
- JPA is the standard, and standards are good!
- Using JPA does not tie you to Hibernate.
- JPA gives you most of the features of plain old Hibernate, except:
- No criteria queries in JPA 2.0. Criteria query is a neat feature of Hibernate that constructs query using Java-based combinators instead of alternate query language, getting the benefit of IntelliSense and Eclipse’s refactoring tools.
- JPA doesn’t have Hibernate’s DeleteOrphan cascade type.
- Delete Orphan is a useful annotation that directs Hibernate to deletes entities in a collection if the parent is deleted, preventing orphaning.
- JPA doesn’t have an equivalent to Hibernate’s ScrollableResults