Help with many to many hql select please

javacoda · **Posted:** Fri Sep 24, 2004 7:40 am

Hibernate version:
2.1.6

Mapping documents:

Code:

<hibernate-mapping package="com.refdb">

    <class name="Release">
        <id name="id">
            <generator class="native"/>
        </id>
        <property name="name" unique="true"/>
        <set name="references" table="reference_release" cascade="all"  >
           <key column="release_id"/>
           <many-to-many column="reference_id" class="com.refdb.Reference"/>
        </set>
    </class>

</hibernate-mapping>

Code:

<hibernate-mapping package="com.refdb">

    <class name="Reference">
        <id name="id">
            <generator class="native"/>
        </id>
        <property name="name" unique="true"/>
        <property name="description"/>
        <property name="owner"/>
        <property name="creationDate"/>
        <property name="readyToMerge"/>
        <property name="conceptOrNL"/>
        <property name="dead"/>
        <set name="releases" table="reference_release" inverse="true" cascade="all">
           <key column="reference_id"/>
           <many-to-many column="release_id" class="com.refdb.Release"/>
        </set>
    </class>

</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():
N/A

Full stack trace of any exception that occurs:
N/A

Name and version of the database you are using:
Oracle 8i

The generated SQL (show_sql=true):
N/A

Debug level Hibernate log excerpt:
N/A

Hi, I am trying to select all References who do not have any relationships to a Release. So any References who's releases collection is empty. Could someone please give me any pointers on how to do this using hql or Criteria?

Many Thanks
Paul

P.S. If Gavin or Christian read this, the synopsis for Hibernate in Action on Amazon.co.uk is wrong, I have emailed them about it, but they haven't changed it. You may want to check it out & contact them http://www.amazon.co.uk/exec/obidos/ASIN/193239415X/qid=1096025848/sr=2-1/ref=sr_2_11_1/026-1055243-7716415

anthony · **Posted:** Fri Sep 24, 2004 7:58 am

from Reference r where r.releases.size = 0

javacoda · **Posted:** Fri Sep 24, 2004 8:06 am

Many thanks Anthony, I didn't realize it would be quite that simple :-) I love Hibernate more every day. I'm counting the days until my copy of Hibernate in Action arrives!

Paul

anthony · **Posted:** Fri Sep 24, 2004 8:07 am

that was in the reference guide... :-/

javacoda · **Posted:** Fri Sep 24, 2004 10:18 am

Thanks, Anthony I have found it in there now. I wouldn't have probably found it though without your help, as my thoughts were off on totally the wrong track, thinking about complicated joins :-)

Once again, many thanks for your help.

Paul