Most efficient way to do a distinct with Criteria API?

jemiller · **Posted:** Tue Feb 15, 2005 1:19 pm

Hibernate version: 3.0beta4

I'm using the Criteria API to issue a query similar to the following. I found out how to use the setResultTransformer() method so that it only returns a single Reservation object for each Reservation object, rather than one for each Item (a reservation can have items in my data model). This is working fine.

Code:

Criteria c = s.createCriteria(Reservation.class)
   .setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
   .createAlias("items", "i")
   .add(Expression.like("i.name", itemName));

However, I'm wondering if maybe there is a more efficient or newer way to do this with the Hibernate 3.0 API since there is the new Projection API or what not. What I'm wondering is if there is a way to tell it to use a "distinct" in the SQL statement that it generates rather than presumably performing the filtering on the client side?

emmanuel · **Posted:** Tue Feb 15, 2005 3:30 pm

in this case the distinct keyword will not give you distinct reservations, since it relies on the distinct SQL keyword