Table per subclass inheritance relationship: How to query against the Parent class without loading any subclass ??? (Hibernate)

Question

Suppose a Table per subclass inheritance relationship which can be described bellow (From wikibooks.org - see here)

Notice Parent class is n

Answer 1

Update: It appears the first option doesn't work as I thought.

First option:

Specify the class in the where clause:

select p from Project p where p.class = Project 

Second option:

Use explicit polymorphism that you can set using Hibernate's @Entity annotation:

@javax.persistence.Entity
@org.hibernate.annotations.Entity(polymorphism = PolymorphismType.EXPLICIT)
@Inheritance(strategy = InheritanceType.JOINED)
public class Project {

    @Id
    private long id;
    ...
}

This is what Hibernate Core documentation writes about explicit polymorphism:

Implicit polymorphism means that instances of the class will be returned by a query that names any superclass or implemented interface or class, and that instances of any subclass of the class will be returned by a query that names the class itself. Explicit polymorphism means that class instances will be returned only by queries that explicitly name that class.

See also

• How to get only super class in table-per-subclass strategy?