Java Reference
In-Depth Information
Support for bulk update/delete
The bulk update and delete in the Criteria API are respectively constructed with
javax.persistence.criteria.CriteriaUpdate and
javax.persistence.criteria.CriteriaDelete interfaces. The following
code demonstrates how to update a lot of information with just one Criteria API re-
//bulk update
CriteriaUpdate cUpdate =
Root root = cUpdate.from(Student.class);
Query q = em.createQuery(cUpdate);
em.getTransaction().begin();//begin transaction
int num = q.executeUpdate();
System.out.println("number of update : "+num);
//JPQL equivalent query
UPDATE Student a SET a.departId = 'GT' WHERE
a.departId = 'GI'
Support for new reserved identifiers
Just like the JPQL, the Criteria API incorporates the possibility of making downcasts
and defines joins using ON conditions. To do that, overloaded treat() methods
have been added to the javax.persistence.criteria.CriteriaBuilder
interface for downcasting, while on() and getOn() methods have been added
to some interfaces (such as Join , ListJoin , SetJoin , MapJoin , Collec-
tionJoin ,and Fetch ) of the javax.persistence.criteria package for joins
with ON conditions. The following query is equivalent to the JPQL downcasting
shown in the preceding code:
Search WWH ::

Custom Search