Is it possible to use analytic functions in Hibernate?

Question

Is there a way to use sql-server like analytic functions in Hibernate?

Something like

select foo from Foo foo where f.x = max(f.x) over (partition by f         


        

Answer 1

Another approach would be to use the mapping. Please see this article: https://forums.hibernate.org/viewtopic.php?f=1&t=998482

I am against the usage of native SQL queries in Hibernate... you lose the benefits of having a mapping:-)

Answer 2

Yes you can, but you will need to extend the hibernate dialect like the following:

import org.hibernate.dialect.Oracle10gDialect;

public class ExtendedDialect extends Oracle10gDialect{
    public ExtendedDialect()
    {
           super();
           registerKeyword("over");
           registerKeyword("partition");
    }
}

Once this class is on your classpath, you will need to tell hibernate to use it instead of the original dialect (in this case Oracle10gDialect). I am not sure which frameworks you are using, but in the case of Spring, you can use the following property under the LocalContainerEntityManagerFactoryBean:

        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="databasePlatform" value="path.to.dialect.ExtendedDialect" />
            </bean>
        </property>

Then you can use over and partition in @Formula annotations, @Where annotations and other hibernate features without confusing hibernate.

Answer 3

You are after a native SQL query.

If you are using JPA the syntax is:

Query q = em.createNativeQuery("select foo.* from Foo foo " +
                               "where f.x = max(f.x) over " +
                               "(partition by f.y)", Foo.class);

If you need to return multiple types, take a look at the SQLResultSetMapping annotation.

If you're using the the Hibernate API directly:

Query q = session.createSQLQuery("select {foo.*} from Foo foo " +
                                 "where f.x = max(f.x) over "+
                                 "(partition by f.y)");
q.addEntity("foo", Foo.class);

See 10.4.4. Queries in native SQL in the Hibernate documentation for more details.

In both APIs you can pass in parameters as normal using setParameter.