@Entity(access = AccessType.FIELD)
@org.hibernate.annotations.Entity(polymorphism = PolymorphismType.EXPLICIT)
@Table(name = "TableA")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class ObjectA{

@Entity(access = AccessType.FIELD)
@Table(name = "TableB")
public class ObjectB extends ObjectA{

When we call ObjectA ("findByKey") the Hibernate always use union select with TableB, but the expect is select only TableA , because we use polymorphism = PolymorphismType.EXPLICIT.

I don't think this is what EXPLICIT is meant for.

How else should it find out which instance to load?

Hibernate, by default, look for class and extends class (PolymorphismType.IMPLICIT (default)). I just want an instance of ObjectA not the ObjectA and all instance of ObjectB extends ObjectA. I don’t want any of their superclasses.

So I try to use PolymorphismType.EXPLICIT, like I did in XML <class...polymorphism="explicit"...>)

But,
@org.hibernate.annotations.Entity(polymorphism = PolymorphismType.EXPLICIT),
don’t work as expect.

ObjectA X.getObjectA(); (return more than one result, because use union select ObjectB)

I’m accepting suggest.

Thanks

Then don't use inheritance.

can you open a jira issue with a running test case of both hbm working and annotations failing. That would help me to see what's wrong.

Looks like this thread is a few years old, but I'm seeing the same thing with Hibernate 3 where PolymorphismType.EXPLICIT is not preventing subclasses from being returned in the results. Hibernate is using a union to include the superclass (which I do want to find) and its subclass (which I don't want to be grabbed polymorphically).

er, sorry, got my threads mixed up. Looks like this issue isn't that old.

Also, I am using annotations and have not tried using the EXPLICIT polymorphism type in a hbm file.

no jira issue has been posted AFAIK