Given
* A simple entity
* A polymorphic entity
When
* querying the simple entity doing a left join with the polymorphic entity
Then
* The results will always be empty when the left joined entity is not present
{code:java}@Entity
@Table(name = "ENTITY_B")
public class EntityB {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "ID")
private Integer id;
@Column(name = "SOME_ID")
private Integer someId;
}{code}
{code:java}@Entity
@Table(name = "ENTITY_A")
@DiscriminatorColumn(name = "DISC_COL", discriminatorType = DiscriminatorType.INTEGER)
public abstract class AbstractEntityA {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "ID")
Integer id;
}{code}
{code:java}@Entity
@DiscriminatorValue("1")
public class EntityAChildOne extends AbstractEntityA {}{code}
{code:java} @Test
public void hhhXXXXTest() throws Exception {
try (Session s = openSession()) {
Transaction tx = s.beginTransaction();
EntityB entityB = new EntityB();
s.persist(entityB);
tx.commit();
}
try (Session s = openSession()) {
Query<EntityB> query = s.createQuery(
"select b from EntityB b left outer join EntityAChildOne a1 on a1.id = b.someId", EntityB.class);
List<EntityB> actual = query.list();
assertThat(actual).hasSize(1);
}
}{code}
{noformat}java.lang.AssertionError:
Expected size:<1> but was:<0> in:
<[]>
at org.hibernate.bugs.ORMUnitTestCase.hhhXXXXTest(ORMUnitTestCase.java:76)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
at org.hibernate.testing.junit4.ExtendedFrameworkMethod.invokeExplosively(ExtendedFrameworkMethod.java:45)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:299)
at org.junit.internal.runners.statements.FailOnTimeout$CallableStatement.call(FailOnTimeout.java:293)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.lang.Thread.run(Thread.java:833){noformat}
In hibernate 5.6.15, this example just works, because hibernate 5 completely ignores the discriminator when generating the SQL (might be a limitation or a bug), but the expected outcome for the example is kept and we get the expected result which is the single list with the entity b in it:
{noformat}Hibernate 5.6.15:
select
entityb0_.ID as id1_1_,
entityb0_.SOME_ID as some_id2_1_
from
MY_TABLE entityb0_
left outer join
ENTITY_A entityachi1_
on (
entityachi1_.ID=entityb0_.SOME_ID
){noformat}
In hibernate 6.2.0, the resulting list will always be empty, because hibernate 6 does not ignore the discriminator, but adds it to the main query criteria (this part is the wrong part). Since this is a left join, the joined entity is optional and adding the discriminator criteria to the main part of the query will result to empty when the joined entity is not present.
{noformat}Hibernate 6.2.0:
select
e1_0.ID,
e1_0.SOME_ID
from
MY_TABLE e1_0
left join
ENTITY_A e2_0
on e2_0.ID=e1_0.SOME_ID
where
e2_0.DISC_COL=1{noformat}
A failing test scenario is to be attached and also available here [https://github.com/ratoaq2/HHH-16438|https://github.com/ratoaq2/HHH-16438|smart-link] |
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