problem with "select new Object ... join ... where"
- by jacob
Hi,
I'm having a problem with an HQL query
Three classes
ClassOne is my BusinessObject
public class ClassOne {
private int id;
private int status;
private Set<ClassTwo> classTwos;
+ other fields/getters/setters/constructor etc
}
ClassTwo is referenced in a set of ClassOne and is kind of the history of an object of ClassOne
public class ClassTwo {
private int id;
private int oldStatus;
private int newStatus;
private String message;
//+ getters/setters/constructor etc
}
ClassThree is my DTO/VO with just one classTwo (not the whole history)
public class ClassThree {
private int id;
private int status;
private ClassTwo classTwo;
public ClassThree(int pId, int pStatus, ClassTwo pClassTwo) {
id=pId;
status=pStatus;
classTwo=pClassTwo;
}
//+ getters/setters etc
}
Now I'd like to create an HQL query like this:
I'd like to get all objects of ClassThree with a certain status and if it exists the newest ClassTwo with a certain newStatus.
For example:
I'd like to get all the DTOs (ClassThree) of ClassOne whose status is now 1, but earlier in their history it has been 2 and I'd like to have the latest ClassTwo object which has 2 as newStatus.
SELECT new ClassThree(c1.id, c1.status, c2)
FROM ClassOne c1
LEFT JOIN c1.classtwos c2 (...)
and (...) is where I don't know what to do, I'm not even sure if it's a join / join fetch
Looked around and tried quite a lot already, but no clue. Especially with the join fetch I get some Hibernate errors like org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list.
Fetching the BusinessObject like that is no problem
SELECT distinct(c1)
FROM ClassOne c1
LEFT OUTER JOIN FETCH c1.classtwos c2
and I get the ClassTwos as my field.
Thanks in advance,
Jacob
P.S.: One thing might be important, ClassTwo has no reference to ClassOne!!
