Hello, I am having some difficulties using inheritance. I am using one table for the base class and two subclasses.
My mapping file contains this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 2.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>

<class name="arbolDeTribunales.NodoArbolTribunales" schema="PRUEBA" table="NODOARBOLTRIBUNALES">
<id column="ID" name="id" type="java.lang.Long">

<generator class="sequence">
<param name="sequence">nodoarboltribunales_seq</param>
</generator>
</id>
<discriminator column="clase"/>
<property column="VALORABSOLUTO" length="10" name="valorAbsoluto" not-null="true" type="java.lang.Double"/>
<property column="PADRE" length="10" name="padre" not-null="true" type="java.lang.Long"/>
<property column="DESCRIPCION" length="300" name="descripcion" type="java.lang.String"/>
<property column="CLASE" length="100" name="clase" not-null="true" type="java.lang.String"/>

<subclass name="arbolDeTribunales.Tribunal">
<property column="SIGLAPAPEL" length="100" name="siglaPapel" type="java.lang.String"/>
<property column="SIGLADIGITAL" length="100" name="siglaDigital" type="java.lang.String"/>
</subclass>

<subclass name="arbolDeTribunales.Jerarquia">
</subclass>
</class>

</hibernate-mapping>

and the code is as follows:

public class TestArbol {
public static void main(String[] args) {
net.sf.hibernate.Session aSession=HM.getSession();


Tribunal unTribunal=new Tribunal(new Double(1),new Long(1));
try {
net.sf.hibernate.Transaction tx = aSession.beginTransaction();
aSession.saveOrUpdate(unTribunal);
System.out.println(tx.toString());
tx.commit();
aSession.close();
} catch (HibernateException e) {
e.printStackTrace();
}



}
}

The stack trace I am getting is this:

net.sf.hibernate.transaction.JDBCTransaction@1922f46
27-ago-2003 12:38:47 net.sf.hibernate.util.JDBCExceptionReporter logExceptions
ADVERTENCIA: SQL Error: 957, SQLState: 42000
27-ago-2003 12:38:47 net.sf.hibernate.util.JDBCExceptionReporter logExceptions
GRAVE: ORA-00957: duplicate column name

27-ago-2003 12:38:47 net.sf.hibernate.JDBCException <init>
GRAVE: Could not synchronize database state with session
java.sql.SQLException: ORA-00957: duplicate column name

at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
at oracle.jdbc.ttc7.Oall7.receive(Oall7.java:573)
at oracle.jdbc.ttc7.TTC7Protocol.doOall7(TTC7Protocol.java:1891)
at oracle.jdbc.ttc7.TTC7Protocol.parseExecuteFetch(TTC7Protocol.java:1093)
at oracle.jdbc.driver.OracleStatement.executeNonQuery(OracleStatement.java:2047)
at oracle.jdbc.driver.OracleStatement.doExecuteOther(OracleStatement.java:1940)
....

Thank you in advance for any help. Mariano

You have to decide if you want to map this column as the discriminator field or as a property of one of your classes.

Actually, he can just use:

I tried modifying the line in the hbm fileand replacing it with
"<property column="CLASE" length="100" name="clase" not-null="true" type="string" insert="false" update="false"/>"
, but still does not work.
I am trying to use the column CLASE as a discriminator, as I read in the reference pdf, I assume hibernate can use this column as a discriminator and by default write there the name of the sublcass. Thank you for your comments. Mariano

You may have another duplicate column in your mappings. Either search for it or look at a full "debug" level log output of Hibernate, where you can see the failed SQL query and column name.

It took me about a day to find out that I was messing up with my hibernate.prperties files. I am working on three projects that use hibernate, each project uses a different schema. I don