jpa – Page 2 – Tarik Billa

JPA’s EntityManager createQuery() vs createNamedQuery() vs createNativeQuery()

July 29, 2023 by Tarik

The createQuery method is used to create dynamic queries, which are queries defined directly within an application’s business logic. Example: public List findWithName(String name) { return em.createQuery( “SELECT c FROM Customer c WHERE c.name LIKE :custName”) .setParameter(“custName”, name) .setMaxResults(10) .getResultList(); } The createNamedQuery method is used to create static queries, or queries that are defined … Read more

How to persist JSR-310 types with Spring Data JPA?

July 29, 2023 by Tarik

UPDATE: The answer below is valid if you need to stay on a Hibernate version < 5.0. Hibernate 5.0 supports persisting JSR-310 date/time types out of the box. I.e. if you are on Hibernate 5.0 or newer, Adam’s answer is the way to go. Everyone else, read on. The root cause for this at none … Read more

Is it possible to output generated SQL using EclipseLink without having to increase log verbosity?

July 29, 2023 by Tarik

Put the following properties in your persistence.xml: <property name=”eclipselink.logging.level.sql” value=”FINE”/> <property name=”eclipselink.logging.parameters” value=”true”/> The latter is helpful, so that the values of the parameter are shown. An alternative is using log4jdbc or log4jdbc-remix.

Testing an EJB with JUnit

May 29, 2023 by Tarik

The accepted answer requires mocking a lot of code, including the persistence layer. Use an embedded container to test the actual beans, instead; otherwise, mocking the persistence layer results in code that barely tests anything useful. Use a session bean with an entity manager that references a persistence unit: @Stateless public class CommentService { @PersistenceContext(unitName … Read more

JPA Criteria API: how to express literal true and literal false?

May 25, 2023 by Tarik

To get an always true Predicate instance, use criteriaBuilder.and(). To get an always false Predicate instance, use criteriaBuilder.or().

Spring boot show sql parameter binding?

May 25, 2023 by Tarik

Add these to application.properties and you should see the logs in details. logging.level.org.hibernate.SQL=debug logging.level.org.hibernate.type.descriptor.sql=trace

How to make a CriteriaBuilder join with a custom “on” condition?

May 23, 2023 by Tarik

It is possible starting from the version 2.1 of JPA using the on method Join<Z, X> on(Predicate… restrictions); Here is how: Root<Order> order = cq.from(Order.class); Join<Order, Item> item = order.join(Order_.itemList, JoinType.LEFT); item.on(cb.equal(item.get(Item_.type), 1));

Are SQL injection attacks possible in JPA?

May 17, 2023 by Tarik

It’s only possible if you’re inlining user-controlled variables in a SQL/JPQL string like so: String sql = “SELECT u FROM User u WHERE id=” + id; If you aren’t doing that and are using parameterized/named queries only, then you’re safe.

IntelliJ IDEA highlights @Entity class names with “Cannot resolve symbol” in JPQL

May 2, 2023 by Tarik

Seems like you have not selected the default JPA provider in facet configuration. Depending upon which provider you are using, pick one from the list. Available options are EclipseLink, Hibernate, OpenJPA, TopLink

Spring Data JPA And NamedEntityGraphs

April 1, 2023 by Tarik

We ran into a similar problem and devised several prospective solutions but there doesn’t seem to be an elegant solution for what seems to be a common problem. 1) Prefixes. Data jpa affords several prefixes (find, get, …) for a method name. One possibility is to use different prefixes with different named graphs. This is … Read more