Hibernate : aggregate two entities in one class to retrieve data with one HQL query -

i have 1 class :

public class bookauthor {    private book book;   private author author; } 

book , author defined entities.

when try retrieve data, way :

final string selectcols = "new bookauthor(b,a)"; final org.hibernate.query q = createquery(selectcols, params, filters); result = q.list(); return result; 

when hibernate executes "q.list()", performs 1 query retrieve book's , author's ids, , iterates results information authors , books. is, in log, there :

select a.id, b.id authors , books b 

and each row :

select a.id, a.name a.id = ?  select b.id, b.title b.id = ? 

is there way tell hibernate results 1 query improve performance ? :

select a.id, a.name, b.id, b.title authors , books b 

thanks in advance.

edit :

entities defined referring tables , column names like:

public static final string table_name = "author"; @column(name = "id", nullable = false) protected long id; 

i think there no db constraint between author , book (this example of actual entities, let's there anonymous books no author). jb nizet, retrieve query , post here in while.

you should not @ hibernate queries sql queries. guess after hibernates lazy-loading:

if fetch bookauthor , properties book , author lazy loaded slow (because hibernate has make 3 querys in total 1 entity)

so depending on situation, can disable lazy loading bookauthor in mapping - hibernate fetch data in 1 select query.