Hi,

I'm in a situation where I'd like the user of a web application to be able to page through a long list of entities. What's the recommended way to handle this in Hibernate?

I looked at the ScrollableResults object but it's not clear to me whether this object can be stored and reused between sessions or not.

Thanks.

I'm a fan of using lazy collections with my application, that way my UI component (In my case, a Tapestry table grid that handles paging automatically) can just re-query each time the page is displayed. Only the records displayed are actually loaded.

This approach only works well if the display set is small (say 25 or less) because each row displayed results in a trip back to the DB (unless the objects are cached). The single query to fetch the collection is fast because only ID's and Version numbers are involved. Note: You can't return lazy results from HQL - you have to use the Criteria API. (Which sucks, in my opinion! Hoping for this feature in H3.) A child collection can simply be mapped as lazy="true",

Another approach is to use a Query object and page through your results one at a time. You can do this using: Query.setMaxResults() and Query.setFirstResult(). The problem here is that you still have to run the query each time, but it limits the results. BTW, this is covered in the FAQ, which is worth reading and will allow you to take off your asbestos underwear when posting to this forum.

There are probably other approaches, but these have worked well for me.

Thanks for the reply. I like the idea of using setFirstResult and setMaxResults. As an old JDBC hand, I'm wondering how these are implemented; I'm thinking probably a scrollable result set? Any idea if it's reasonably efficient to retrieve, say, the middle 100 items in a list of several million?

Thanks.

this is done with database-specific functions like "select first x start y ..."

I'm using Oracle 8, I don't think it supports any keywords like FIRST or START. How do you handle it in this case?

test and read generated sql