java - JPA Criteria API - Setup Joins and Fetch data from Joined Entity -

i have 2 entities foo , fooderiveddata, described below.

entity foo:

@entity @table(name="foo") public class foo {  // skipping property declarations  @onetoone @primarykeyjoincolumn(name = "foo_id") @fetch(fetchmode.join) public getfooderiveddata() {     return fooderiveddata; } 

entity fooderiveddata

@entity @table(name = "foo_derived_vw") @immutable public class fooderiveddata {      @id     @column(name = "foo_id")     long fooid;      @column(name = "foo_count")     private integer foocount;      @column(name = "foo_sum")     private bigdecimal foosum;       // getters left out here 

i working jpa criteria api (hibernate jpa implementation) , need instance of fooderiveddata loaded in foo. fetched eagerly default, want fetched using inner join, not separate select statement every instance of fooderiveddata. able add inner join against fooderiveddata.

criteriaquery<foo> criteriaquery = criteriabuilder.createquery(foo.class); root<foo> root = criteriaquery.from(foo.class); root.join("fooderiveddata"); predicate p = getpredicate(); // details omitted here criteriaquery.select(root).where(p); 

although can see sql in logs inner join added foo_derived_vw, none of columns selected. every instance of foo, still need have separate select statement data have readily available.

currently query this:

select f.foo_id, f.foo_bar from foo f inner join foo_derived_vw d on d.foo_id = f.foo_id; select d.foo_id, d.foo_count, d.foo_sum foo_derived_vw d foo_id = ?; select d.foo_id, d.foo_count, d.foo_sum foo_derived_vw d foo_id = ?; 

note not selecting data joined foo_derived_vw , data being fulfilled additional database hits. want query this:

select f.foo_id, f.foo_bar, d.foo_count, d.foo_sum from foo f inner join foo_derived_vw d on d.foo_id = f.foo_id; 

how select properties joined entity in criteria api? can instruct javax.persistence.criteria.root select attributes joining?

i have attempted changing join fetch, or fetch specified join type. in either case, it's failing hibernate queryexception.

root<foo> root = criteriaquery.from(foo.class); root.fetch("fooderiveddata"); 

caused by: org.hibernate.queryexception: query specified join fetching, owner of fetched association not present in select list

i believe don't need specify fetchmode getfooderiveddata() default fetch type onetoone relationship eager. hope helps!