@NamedQuery over @NamedNativeQuery

Question

Is there any benefit of using @NamedQuery over @NamedNativeQuery in hibernate or vice verse. I cant spot the exact difference or in which context we should use @NamedQuery over @NamedNativeQuery

Thanks in advance.

Answer 1

@NamedNativeQuery lets you write a named SQL query, while @NamedQuery lets you write a named HQL query (or JPQL).

In general, you should prefer to write HQL queries because then you can let Hibernate handle the intricacies of converting the HQL into the various SQL dialects. This will make your job much simpler when you choose to switch DBMS providers.

Answer 2

When taking about performance, you have to know something about what goes on under the hood.

You have probably programmed something using straightforward JDBC, so you know how to queries get passed to the driver and send to the database. When using HQL or JPA-QL the queries first have to be parsed into an SQL language that the database can understand. In this case, we have an extra parsing step in between. Note that Native SQL queries, including stored procedure calls, the persistence framework still takes care of mapping the JDBC result sets to graphs of persistent objects.

If you want to include a native SQL hint to instruct the database management systems query optimizer, for example, you need to write the SQL yourself. HQL and JPA-QL do not have keywords for this.

The disadvantage of putting native SQL in your mapping metadata is lost database portability, because your mappings, and hence your application, will work only for a particular database. But usually this is of a minor concern as you are probably not creating a framework that has to work on every database.

When you want to get behind the performance of your query, you really have to consult the database and look at the execution plan - A DBA can tell you exactly what is good and what can be optimized.