Getting large result sets using hibernate

[M Burke]

I need to get data from a large table. So I want to get it in segments, like ten rows at a time, so I don't blow up the memory. Is there a way I can do this with hibernate?

I might have to write some HQL or a stored procedure, which is ok, I am just not sure what the syntax would be.

[Scott Selikoff]

Moving to object relational mapping forum...

[Mark Spritzler]

This in the Hibernate docs on pagination, to get a certain number of records at a time

http://www.hibernate.org/hib_docs/v3/reference/en/html/objectstate.html#objectstate-querying-executing-pagination

Mark

[Cameron Wallace McKenzie]

I find the Hibernate Criteria API makes this very easy to do:

   
public class FindFirstFive {
 public static void main(String args[]) {
  User user = new User();
  Session session = HibernateUtil.beginTransaction();
  Criteria criteria = session.createCriteria(User.class);
  criteria.setFirstResult(0);
  criteria.setMaxResults(5);
  List results = criteria.list();
  HibernateUtil.commitTransaction();
  for (int i = 0; i<results.size(); i++) {
    System.out.println(results.get(i).toString());
  }
 }
}
 

These two lines of code help to limit your results. Just use a counter, and you can easily allow clients to page through your results.


criteria.setFirstResult(0);
criteria.setMaxResults(5);

Tutorial on Using the Criteria API from Hibernate

-Cameron McKenzie

[M Burke]

Yes, that works. Thanks

[Mark Spritzler]

The one thing that I would add, is for me the Criteria object just for pagination is not using the Criteria object wisely. I prefer HQL for this kind of work. The Criteria I find better for simpler queries and also for those Example queries and ad hoc queries based on Search screens.

Mark

[santhosh john]

I have an example for toplink here.traversing large result sets