Composite Identifier class and createQuery

ed4becky · **Joined:** Tue Nov 22, 2005 5:44 pm **Posts:** 3

I have create a Composite Identifier class called PatKey, which I use to retrieve a Pat object (which includes a PatKey id; field).

The session.get() works fine with the PatKey as a parameter. However, if I try to use createQuery() with the following HQL:

session.createQuery("from Pat as p where p.hosp_id = :hospId"
+ " and p.pat_num = :patNum and p.ver_seq = :verSeq");

(where :hospId, :patNum, :verSeq are the elementsa of PatKey), I get the following error:

org.hibernate.QueryException: could not resolve property: hosp_id of: org.ed4becky.hibernate.hibernate.Pat

Makes sense to me, since there is no hosp_id in the Pat class (it's in thye id filed, which contaoins the PatKey reference).

What is the best way if I want to retrieve multiple Pat objects based on part of the primary key, and (possibly) some other field(s)? IE how do I use createQuery when a Composite Identier clkass is involved?

momania · **Posted:** Tue Nov 22, 2005 5:59 pm

try using:

Code:

session.createQuery("from Pat as p where p.id.hosp_id = :hospId"
+ " and p.id.pat_num = :patNum and p.ver_seq = :verSeq"); 

insert id. :)

ed4becky · **Joined:** Tue Nov 22, 2005 5:44 pm **Posts:** 3

momania wrote:

insert id. :)

Thanx! That almost did it! I also had to change from using table column names to using object field names! (makes sense).

Appreciate the quick response!

momania · **Posted:** Wed Nov 23, 2005 2:58 am

ed4becky wrote:

momania wrote:

insert id. :)

Thanx! That almost did it! I also had to change from using table column names to using object field names! (makes sense).

Appreciate the quick response!

In HQL you can use the object's attribute names in stead of the table column names indeed. :)

so. "from Object o where o.id.xValue = :x and o.otherAttribute = :other"

You can use that as far as your references go. :)

hhuber · **Posted:** Wed Nov 23, 2005 5:21 am

You've got some other alternatives:

Code:

session.get( Pat.class, patKey );  // returns null if not found
session.load( Pat.class, patKey );  // undefined result if not found
session.createCriteria( Pat.class ).add( Restrictions.idEq( patKey ) ).uniqueResult();  // should return null if not found; other conditions possible, too (what for though)

And I think there should be some possibility to formulate the condition like " p.id = :id ". It just couldn't work it out yet ;-)