hibernate.md

Hibernate

Bean Conventions and Immutability

One of my pet peeves with Hibernate is that it needs setter methods to fill the Java object with content. As I'm very much for immutability, this was just a no-go for me. It turns out it was somewhat of misconception. You still need setter (and getter methods), but they access can be set to private, making them at least immutable on an API level

For some more details, have a look at this article

Using native queries

Issuing native sql queries

sess.createSQLQuery("SELECT * FROM CATS").list();

will return a List of Object arrays (Object[]) with scalar values for each column.

Hibernate will use ResultSetMetadata to deduce the actual order and types of the returned scalar values. To avoid that or to simply be more explicit in what is returned:

sess.createSQLQuery("SELECT * FROM CATS")
 .addScalar("ID", Hibernate.LONG)
 .addScalar("NAME", Hibernate.STRING)
 .addScalar("BIRTHDATE", Hibernate.DATE)
This query specified:

This will return Object arrays, but now it will not use ResultSetMetadata but will instead explicitly get the ID, NAME and BIRTHDATE column as respectively a Long, String and a Short from the underlying resultset. This also means that only these three columns will be returned, even though the query is using * and could return more than the three listed columns.