how to get count with a namedquery, without getting all the list (it would increase performance I think). This is the named query that doesn't work:
@NamedQuery(name = "Charakteristika.findAllCount", query = "SELECT COUNT(c) FROM Charakteristika c")
Executing this:
System.out.println("a");
System.out.println(em.createNamedQuery("Charakteristika.findAllCount", Integer.class).getSingleResult().intValue());
System.out.println("b");
Output:
a
Although this query works:
@NamedQuery(name = "Charakteristika.findAll", query = "SELECT c FROM Charakteristika c")
Executing this:
System.out.println("a");
System.out.println(em.createNamedQuery("Charakteristika.findAll", Charakteristika.class).getResultList().size());
System.out.println("b");
Output:
a
11111
b
Change your code likes this;
int count = ((Number)em.createNamedQuery("Charakteristika.findAllCount").getSingleResult()).intValue();
System.out.println(count);