hql

I've been using spring and hibernate for this past few weeks and I've always been learning something new there. Right now I've got a problem that I want to solve with Projections in Hibernate. Suppose there is a model Person and that model has many Car . The following are how the class definitions roughly gonna look like: public class Person implements java.io.Serializable { private Integer id; private String name; private List<Car> cars; private Integer minYear; // Transient private Integer maxYear; // Transient } public class Car implements java.io.Serializable { private Integer id; private

Suppose I have a map: <map name="externalIds" table="album_external_ids"> <key column="album_id" not-null="true"/> <map-key-many-to-many class="Major" column="major_id"/> <element column="external_id" type="string" not-null="true"/> </map> How do I make a HQL meaning "select entities where map key's id == :foo and map value == :bar"? I can join it using select album from Album album join album.externalIds ids But how would I then refer to ids' key and value? ids.key.id = :foo and ids.value = :bar doesn't work, and hibernate doc is silent on this topic. Naive approaches that didn't work: select

I have a Hibernate HQL question. I'd like to write a subquery as a derived table (for performance reasons). Is it possible to do that in HQL? Example: FROM Customer WHERE country.id in (SELECT id FROM (SELECT id FROM Country where type='GREEN') derivedTable) (btw, this is just a sample query so don't give advice on rewriting it, is just the derived table concept I'm interested in) Unfortunately no, derived tables don't currently work in HQL. For example, the following works: List<int> result = nHSession.CreateQuery( @"select distinct Id from User u") .List<int>().ToList(); ...the following

What is the equivalent of row_number() over partition in hql I have the following query in hql: select s.Companyname, p.Productname, sum(od.Unitprice * od.Quantity - od.Discount) as SalesAmount FROM OrderDetails as od inner join od.Orders as o inner join od.Products as p " + "inner join p.Suppliers as s" + " where o.Orderdate between '2010/01/01' and '2014/01/01' GROUP BY s.Companyname,p.Productname" I want to do partition by s.Companyname where RowNumber <= n . As far as I know you cannot use row_number() neither in HQL nor in JPQL . I propose to use a native SQL query in this case:

I'd like to "dry-run" Hibernate HQL queries. That is I'd like to know what actual SQL queries Hibernate will execute from given HQL query without actually executing the HQL query against real database. I have access to hibernate mapping for tables, the HQL query string, the dialect for my database. I have also access to database if that is needed. Now, how can I find out all the SQL queries Hibernate can generate from my HQL without actually executing the query against any database? Are there any tools for this? Note, that many SQL queries can be generated from one HQL query and the set of

I have been trying different combinations of HQL and Criteria and I haven't been able to avoid some unnecessary joins (in both) and some unnecessary selects (in Criteria). In our scenario, we have a @ManyToMany relationship between Segment and Application entities (navigation is from Segment to Applications). First I tried this Criteria : Application app = ... List<Segment> segments = session.createCriteria(Segment.class) .createCriteria(Segment.APPLICATIONS) .add(Restrictions.idEq(app.getId())) .list(); Wich produces this SQL: select this_.id as id1_1_, this_.description as descript2_1_1_,

I'm a little confused about how to do something in HQL. So let's say I have a class Foo that I'm persisting in hibernate. It contains a set of enum values, like so: public class Foo { @CollectionOfElements private Set<Bar> barSet = new HashSet<Bar>(); //getters and setters here ... } and public enum Bar { A, B } Is there an HQL statement I can use to fetch only Foo instances who'se barSet containst Bar.B? List foos = session.createQuery("from Foo as foo " + "where foo.barSet.contains.Bar.B").list(); Or am I stuck fetching all Foo instances and filtering them out at the DAO level? List foos =