A novice question, listing my relations?

inkimar · **Joined:** Sat Jun 24, 2006 6:26 pm **Posts:** 10

Hello!

Wrote my first hibernateapplication taken from the reference-guide 'Introduction to Hibernate'. The relation described is many-to-many.
The tables are EVENTS,PERSON_EVENT and PERSON.
The examples gives you the idea on how to create an event, create a person and then link them together through PERSON_EVENT.

The example does not show you how to show the events for a particular person. The way to do this using ordinary SQL would be ( not using JOIN here).

'select E.Title ,P.firstname from EVENT E, PERSON_EVENT X ,PERSON P where E.event_id=X.event_id and X.person_id=P.person_id and p.person_id=7'

Giving me the title of the event and firstname for person_id=7.

What would be the best way to do this in Hibernate, following the example in chapter 1 ?

Best regards, i

pasha · **Joined:** Sat Nov 27, 2004 4:13 am **Posts:** 137

select ev from Event as ev, ev.persons as prs where prs.id = ?

inkimar · **Joined:** Sat Jun 24, 2006 6:26 pm **Posts:** 10

will check out your solution this evening,
and then do my homework on HSQL.

Thanks!

- i

inkimar · **Joined:** Sat Jun 24, 2006 6:26 pm **Posts:** 10

Hello Pasha!

If you read the chapter 1 , http://www.hibernate.org/hib_docs/v3/re ... orial.html .

Then you can see that there is no 'persons' in the Class Event.

Please check the example in ch1. again.
The only mapping is the following:

Code:

<class name="events.Person" table="PERSON">
    <id name="id" column="PERSON_ID">
        <generator class="native"/>
    </id>
    <property name="age"/>
    <property name="firstname"/>
    <property name="lastname"/>

    <set name="events" table="PERSON_EVENT">
        <key column="PERSON_ID"/>
        <many-to-many column="EVENT_ID" class="events.Event"/>
    </set>

</class>

is your suggestion that I create a 'Set person' in the Event-Class and
change the mapping in event.hbm.xml.

Please ge back to me and explain.

regards, i