Named queries

A named query in JPA, as the name suggest, is a query you define and associate with your entities, which are given unique names, that can be used later to create the query without re-specifying its syntax. This way, you can remove the same query multiple times, without having to write it again.

To define a named query, we will annotate our entity with the @NamedQuery annotation, specifying the name and the query itself, as shown in the following example:

@Entity 
@NamedQuery(name = "fetchAllMovies", query = "SELECT m FROM Movie m") 
public class Movie { 
.... 
} 

Then, in order to use this query, we will use the createNamedQuery method, passing the name of our query, as shown in the following example:

Query q = entityManager.createNamedQuery("fetchAllMovies"); 
List<Movie> movies = q.getResultList(); 

Of course, we can specify queries with named parameters, as shown in the following example:

@Entity 
@NamedQuery(name = "fetchMovie", query = "SELECT m FROM Movie m 
WHERE m.id...