JPA（2.0）标准简单联接

Question

I am having problem creating criteriaQuery for the following sql. Any help would be appreciated.Lets say I have two tables Member and Person. I am joining on name and age and having where clause for both of the table. I am using OpenJPA(2.0)

select * 
from Member
join Person
on Member.name = Person.name 
    and Member.age = Person.age
where Member.name = 'someOne'
and Member.age = '24'
and Person.gender = 'F'
and Person.type = 'employee' 

Answer 1

How about something like this:

CriteriaBuilder builder = em.getCriteriaBuilder();
CriteriaQuery<Tuple> criteria = builder.createTupleQuery();
Root<Member> fromMember = criteria.from(Member.class);
Root<Person> fromPerson = criteria.from(Person.class);
criteria.multiselect(fromMember, fromPerson);
List<Predicate> predicates = new ArrayList<Predicate>();
predicates.add(builder.equal(fromMember.get(Member_.name), fromPerson.get(Person_.name)));
predicates.add(builder.equal(fromMember.get(Member_.age), fromPerson.get(Person_.age)));
predicates.add(builder.equal(fromMember.get(Member_.name), "someOne"));
predicates.add(builder.equal(fromMember.get(Member_.age), 24));
predicates.add(builder.equal(fromPerson.get(Person_.gender), "F"));
predicates.add(builder.equal(fromPerson.get(Person_.type), "employee"));
criteria.where(predicates.toArray(new Predicate[predicates.size()]));
List<Tuple> result = em.createQuery(criteria).getResultList();

This will return a 2-element tuple made up of Member and Person. You can enumerate the individual fields in the call to multiselect if you would rather have individual fields in each tuple.