Queries are useful not only for finding objects, but for efficiently deleting them as well. For example, you might delete all records created before a certain date. Rather than bring these objects into memory and delete them individually, JPA allows you to perform a single bulk delete based on JPQL criteria.

Delete by query uses the same JPQL syntax as normal queries, with one exception: begin your query string with the delete keyword instead of the select keyword. To then execute the delete, you call the following Query method:

public int executeUpdate ();

This method returns the number of objects deleted. The following example deletes all subscriptions whose expiration date has passed.

Query q = em.createQuery ("delete s from Subscription s where s.subscriptionDate < :today");
q.setParameter ("today", new Date ());
int deleted = q.executeUpdate ();