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Using one mapping file works just fine, but splitting the subclasses into separate mapping files does not...

Hibernate version:3.0RC1

Mapping documents:<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="example">
<class name="Person" table="person" discriminator-value="Person">
<id name="id" column="person_id" type="long" unsaved-value="null">
<generator class="hilo"/>
</id>
<discriminator column="subtype" type="string"/>
<property name="name" column="name" type="string" length="30" not-null="true"/>
<property name="age" column="age" type="float"/>
<!--subclass name="Parent" discriminator-value="Parent">
<set name="children" inverse="false" cascade="all" lazy="true">
<key column="parent_id" />
<one-to-many class="Child"/>
</set>
</subclass-->
<!--subclass name="Child" discriminator-value="Child">
<many-to-one name="parent" class="Parent" column="parent_id" not-null="false"/>
</subclass-->
</class>
</hibernate-mapping>
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="example">
<subclass name="Parent" extends="Person" discriminator-value="Parent">
<set name="children" inverse="false" cascade="all" lazy="true">
<key column="parent_id" />
<one-to-many class="Child"/>
</set>
</subclass>
</hibernate-mapping>
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="example">
<subclass name="Child" extends="Person" discriminator-value="Child">
<many-to-one name="parent" class="Parent" column="parent_id"
not-null="false"/>
</subclass >
</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:

Name and version of the database you are using:

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:Buildfile: C:\Documents and Settings\Peter2\workspace\HibernateTest3\build.xml
schemaexport:
[schemaexport] 00:00:07,656 INFO Environment:456 - Hibernate 3.0rc1
[schemaexport] 00:00:07,718 INFO Environment:474 - loaded properties from resource hibernate.properties: {hibernate.order_updates=true, hibernate.default_batch_fetch_size=8, hibernate.connection.driver_class=org.postgresql.Driver, hibernate.cglib.use_reflection_optimizer=true, hibernate.cache.provider_class=org.hibernate.cache.HashtableCacheProvider, hibernate.max_fetch_depth=1, hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect, hibernate.jdbc.use_streams_for_binary=true, hibernate.query.substitutions=yes 'Y', no 'N', hibernate.proxool.pool_alias=pool1, hibernate.connection.username=peter, hibernate.cache.region_prefix=hibernate.test, hibernate.connection.url=jdbc:postgresql://localhost/hibernatetest3, hibernate.show_sql=true, hibernate.connection.password=****, hibernate.jdbc.batch_versioned_data=true, hibernate.connection.pool_size=1}
[schemaexport] 00:00:07,718 INFO Environment:501 - using java.io streams to persist binary types
[schemaexport] 00:00:07,734 INFO Environment:502 - using CGLIB reflection optimizer
[schemaexport] 00:00:07,734 INFO Environment:532 - using JDK 1.4 java.sql.Timestamp handling
[schemaexport] 00:00:07,765 INFO Configuration:219 - Mapping file: C:\Documents and Settings\Peter2\workspace\HibernateTest3\src\example\child.hbm.xml
[schemaexport] 00:00:08,250 INFO Configuration:219 - Mapping file: C:\Documents and Settings\Peter2\workspace\HibernateTest3\src\example\parent.hbm.xml
[schemaexport] 00:00:08,343 INFO Configuration:219 - Mapping file: C:\Documents and Settings\Peter2\workspace\HibernateTest3\src\example\person.hbm.xml
[schemaexport] 00:00:08,421 INFO HbmBinder:256 - Mapping class: example.Person -> person
[schemaexport] 00:00:08,671 INFO Dialect:89 - Using dialect: org.hibernate.dialect.PostgreSQLDialect
[schemaexport] 00:00:08,890 INFO Configuration:844 - processing extends queue
[schemaexport] 00:00:09,046 INFO HbmBinder:733 - Mapping subclass: example.Parent -> person
[schemaexport] 00:00:09,062 INFO Configuration:848 - processing collection mappings

BUILD FAILED
C:\Documents and Settings\Peter2\workspace\HibernateTest3\build.xml:50: Schema text failed: Association references unmapped class: example.Child

Total time: 9 seconds

how do you build the configuration ?

show that code and your cfg.xml

The problem I had was when running the schema export tool 3.0 alpha 1. The config file isn't used there is it? Anyway, my config file and test code looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory name="PostgreConnectionFactory">
<property name="hibernate.connection.username">peter</property>
<property name="hibernate.connection.password">carina2004</property>
<property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="hibernate.connection.url">jdbc:postgresql://localhost/hibernatetest3</property>
<property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
</session-factory>
</hibernate-configuration>


package example;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

public class Test {

public static void main(String[] args) throws Exception {
Configuration cfg = new Configuration();
cfg.addClass(Person.class);
// cfg.addClass(Parent.class); // cannot get separate mapping file to work!
// cfg.addClass(Child.class); // cannot get separate mapping file to work!
SessionFactory factory = cfg.buildSessionFactory();
Session session = factory.openSession();
Transaction tx = null;

try {
tx = session.beginTransaction();

Parent peter = new Parent();
peter.setName("Peter");
peter.setAge(42f);
Set<Child> children = new HashSet<Child>();

Child martin = new Child();
martin.setName("Martin");
martin.setAge(4f);
martin.setParent(peter);

Child clara = new Child();
clara.setName("Clara");
clara.setAge(1.5f);
clara.setParent(peter);

children.add(martin);
children.add(clara);
peter.setChildren(children);

// session.save(clara);
// session.save(martin);
session.save(peter);

tx.commit();

} catch (Exception e) {
if (tx != null)
tx.rollback();
throw e;
} finally {
session.close();
}
}
}

ok - please explain if its only in schemaexport or in your program it fails.

The problem is that the schemaexport tool doesn't seem to handle separate mapping files. If I use one mapping file (person.hbm.xml) the code works.

use a hibernate.cfg.xml should work.