" Consider the two entities:
\r\n\r\n {code:java}
class \r\nclass Parent {
\r\n @Id
\r\n private long id;
\r\n\r\n @OneToOne(mappedBy = \ "parent \ ")
\r\n private Child child;
\r\n }
\r\n {code}
and
\r\nand\r\n\r\n {code:java}
\r\n @Entity
class \r\nclass Child {
\r\n @Id
\r\n private long id;
\r\n\r\n @OneToOne
\r\n private Parent parent;
\r\n }
\r\n {code}
The following \r\n\r\nThe JPQL-query \ "from Parent p where p.child is null \ " should list all parents that don't have a child.
The \r\nThe actual SQL that is generated looks like this:
\r\n {code:sql}
select
\r\nselect\r\n parent0_.id as id1_1_
\r\n from
\r\n Parent parent0_
\r\n where
\r\n parent0_.id is null
\r\n {code}
This \r\nThis query always returns an empty result, because the pk of person is never null!
Testcase \r\n\r\nTestcase :
\r\n\r\n {code:java}
package \r\npackage org.hibernate.bugs;
import \r\n\r\nimport static org.assertj.core.api.Assertions.assertThat;
import \r\n\r\nimport java.util.List;
import \r\n\r\nimport javax.persistence.CascadeType;
import \r\nimport javax.persistence.Entity;
import \r\nimport javax.persistence.EntityManager;
import \r\nimport javax.persistence.EntityManagerFactory;
import \r\nimport javax.persistence.Id;
import \r\nimport javax.persistence.OneToOne;
import \r\nimport javax.persistence.Persistence;
import \r\nimport javax.persistence.Query;
import \r\n\r\nimport org.junit.After;
import \r\nimport org.junit.Before;
import \r\nimport org.junit.Test;
\r\n\r\n /**
\r\n * This template demonstrates how to develop a test case for Hibernate ORM, using the Java Persistence API.
\r\n */
public \r\npublic class JPAUnitTestCase {
\r\n\r\n private EntityManagerFactory entityManagerFactory;
\r\n\r\n @Before
\r\n public void init() {
\r\n entityManagerFactory = Persistence.createEntityManagerFactory( \ "templatePU \ ");
\r\n }
\r\n\r\n @After
\r\n public void destroy() {
\r\n entityManagerFactory.close();
\r\n }
\r\n\r\n // Entities are auto-discovered, so just add them anywhere on class-path
\r\n // Add your tests, using standard JUnit.
\r\n @Test
\r\n public void hhh123Test() throws Exception {
\r\n EntityManager entityManager = entityManagerFactory.createEntityManager();
\r\n\r\n runInTransaction(entityManager, () -> {
\r\n Parent parent1 = new Parent(1);
\r\n new Child(3, parent1);
\r\n entityManager.persist(parent1);
\r\n\r\n Parent parent2 = new Parent(2);
\r\n entityManager.persist(parent2);
\r\n });
\r\n\r\n runInTransaction(entityManager, () -> {
\r\n Query query = entityManager.createQuery( \ "from Parent p where p.child is null \ ");
\r\n @SuppressWarnings( \ "unchecked \ ")
\r\n List<Parent> parents = query.getResultList();
\r\n assertThat(parents).hasSize(1);
\r\n assertThat(parents).element(0).extracting(Parent::getId).isEqualTo(2);
\r\n });
\r\n\r\n entityManager.close();
\r\n }
\r\n\r\n private void runInTransaction(EntityManager entityManager, Runnable runnable) {
\r\n entityManager.getTransaction().begin();
\r\n runnable.run();
\r\n entityManager.getTransaction().commit();
\r\n entityManager.clear();
\r\n }
\r\n }
\r\n\r\n\r\n @Entity
class \r\nclass Parent {
\r\n @Id
\r\n private long id;
\r\n\r\n @OneToOne(mappedBy = \ "parent \ ", cascade = CascadeType.ALL)
\r\n private Child child;
\r\n\r\n Parent() {}
\r\n\r\n public Parent(long id) {
\r\n this.id = id;
\r\n }
\r\n\r\n public long getId() {
\r\n return id;
\r\n }
\r\n\r\n public Child getChild() {
\r\n return child;
\r\n }
\r\n\r\n void setChild(Child child) {
\r\n this.child = child;
\r\n }
\r\n\r\n @Override
\r\n public String toString() {
\r\n return \ "Parent [id= \ " + id + \ ", child= \ " + child + \ "] \ ";
\r\n }
\r\n }
\r\n\r\n\r\n @Entity
class \r\nclass Child {
\r\n @Id
\r\n private long id;
\r\n\r\n @OneToOne
\r\n private Parent parent;
\r\n\r\n Child() {}
\r\n\r\n public Child(long id, Parent parent) {
\r\n this.id = id;
\r\n setParent(parent);
\r\n }
\r\n\r\n public Parent getParent() {
\r\n return parent;
\r\n }
\r\n\r\n public void setParent(Parent parent) {
\r\n this.parent = parent;
\r\n parent.setChild(this);
\r\n }
\r\n\r\n @Override
\r\n public String toString() {
\r\n return \ "Child [id= \ " + id + \ "] \ ";
\r\n }
\r\n }
\r\n {code} " |
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