Hibernate Query Returns Duplicate Rows

[Casey Kcins]

Okay. I have a weird question I was wondering if someone can help me out with. I have a method that's job is basically to return the entire table. It works, but returns the same row twice. Is there something I'm doing wrong with the iterator?

public void TestListAllAppointments() {
setUp(); //puts 4 rows into the database.
Configuration cfg = new Configuration();
SessionFactory factory = cfg.configure().buildSessionFactory();
Session session = factory.openSession();

Query q = session.createQuery("from Appointment");
List results = q.list();
 
                //some tests, results should be 4
System.out.println("q list: " + q.list().size()); //is 8
System.out.println("results: " + results.size()); //is 8

Iterator iter = q.list().iterator();
if (!iter.hasNext()) {
            System.out.println("No Appointments to display.");
            return;
        }
 while (iter.hasNext()) {
            Appointment a = (Appointment) iter.next();
            String msg = a.getDescription();
            System.out.println(msg);
        }
tearDown(); //removes everything from the database
}

So... any ideas why I'm getting twice as many rows? Do you need to see any more code then I've displayed?

[Casey Kcins]

Okay, well that's really weird.
The Database name is Appointment

I have an Appointment class, and a DoctorsAppointment class (which extends Appointment).

When I set up my query (from Appointment), for some reason, it grabbed it for both Appointment, and DoctorsAppointment. Which doubled the result.

When I queried (from DoctorsAppointment), which is not the name of the table, I got the correct result set.

Huh.

-- Casey Kcins

[Mark Spritzler]

When you declare inheritance mapping, the type of mapping you do will change the type of query that is run, if you use <union-subclass> (table per implemented subclass) the query will unionize the subclass tables into one result set, which might cause your duplicate rows. a <joined-subclass> (third normal form data tables) will do a join between the parent and child tables, which might be more of what you are looking for, and finally <subclass> is for a single table.

What do your tables look like, and how did you map them?

mark

[Casey Kcins]

I actually didn't map the parent class to the subclass.
I had no idea that was something you should do until you mentioned it.
Then I looked it up http://www.hibernate.org/hib_docs/reference/en/html/inheritance.html

When I set it up in the application, I only called the subclass (DoctorsAppointment). There isn't a use for the main class really.

There won't be any subclasses to the main class (Appointment), so I don't think I'll need to do that mapping.

Good to know though.

[Mark Spritzler]

Originally posted by Casey Kcins:
I actually didn't map the parent class to the subclass.
I had no idea that was something you should do until you mentioned it.
Then I looked it up http://www.hibernate.org/hib_docs/reference/en/html/inheritance.html

When I set it up in the application, I only called the subclass (DoctorsAppointment). There isn't a use for the main class really.

There won't be any subclasses to the main class (Appointment), so I don't think I'll need to do that mapping.


I'm confused, you made a Appointment class then subclassed it with DoctorsAppointment, but you don't ever expect to need to subclass Appointment ever again, no DentistsAppointment, or AccountantAppointment?

If that is the case, my question is why have that Appointment superclass?

Mark
Good to know though.

[Casey Kcins]

If that is the case, my question is why have that Appointment superclass?

Neurosis?

No. It bothered me that since I was making a many-to-one relationship with the doctor class, I needed to reference Doctor in Appointment. But... It may not necisarrily be a 'doctors appointment'. Even though there may never be another subclass, it just felt right creating one to reference the Doctor class.

<shrugs>

-- Casey Kcins