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Hibernate version: 3 
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">
<!-- Generated 03.08.2006 00:21:12 by Hibernate Tools 3.1.0.beta5 -->
<hibernate-mapping>
    <class name="de.xxx.webapplication.kennzahlmgmt.jdo.Tbluser" table="tbluser" catalog="kenny">
        <comment></comment>
        <id name="idtblUser" type="int">
            <column name="idtblUser" />
            <generator class="assigned" />
        </id>
        <many-to-one name="tbldevison" class="de.xxx.webapplication.kennzahlmgmt.jdo.Tbldevison" fetch="select">
            <column name="tblDevison_idtblDevison" not-null="true">
                <comment></comment>
            </column>
            <column name="tblDevison_tblDevisonGroupe_idtblDevisonGroupe" not-null="true">
                <comment></comment>
            </column>
        </many-to-one>
        <property name="name" type="string">
            <column name="name" length="45" not-null="true">
                <comment></comment>
            </column>
        </property>
        <property name="vorname" type="string">
            <column name="vorname" length="45" not-null="true">
                <comment></comment>
            </column>
        </property>
        <property name="pwd" type="string">
            <column name="pwd" length="20" not-null="true">
                <comment></comment>
            </column>
        </property>
        <property name="userid" type="string">
            <column name="userid" length="20" not-null="true">
                <comment></comment>
            </column>
        </property>
        <property name="aktiv" type="java.lang.Boolean">
            <column name="aktiv">
                <comment></comment>
            </column>
        </property>
        <property name="nummer" type="string">
            <column name="nummer" length="45">
                <comment></comment>
            </column>
        </property>
        <set name="tblroleHasTblusers" inverse="true">
            <key>
                <column name="tblUser_idtblUser" not-null="true">
                    <comment></comment>
                </column>
            </key>
            <one-to-many class="de.xxx.webapplication.kennzahlmgmt.jdo.TblroleHasTbluser" />
        </set>
    </class>
</hibernate-mapping>
Code between sessionFactory.openSession() and session.close():
Transaction myTransaction = null; //mySession.beginTransaction();;
		 try {
		 //Transaction öffnen
		 /*Transaction*/ myTransaction = mySession.beginTransaction();
		 
		 //User Tabellen befüllen 
		 Tbluser dbUser = new Tbluser();//(Tbluser)mySession.load(Tbluser.class, user.getId() );
		 
		 dbUser.setAktiv(true);
		 dbUser.setName(user.getName());
		 dbUser.setNummer(user.getNummer());
		 dbUser.setPwd(user.getPasswort());
		 dbUser.setTbldevison(myDevison);
		 dbUser.setVorname(user.getVorname());
		 dbUser.setUserid(user.getKennung());
		 
		 Integer newId = (Integer) mySession.save(dbUser);
                 myTransaction.commit();
	    } catch( HibernateException ex ) {
	      if( myTransaction != null )
	        try { myTransaction.rollback(); } catch( HibernateException exRb ) {}
	      throw new RuntimeException( ex.getMessage() );
	    } finally {
	      try { /*mySession.close();*/ } catch( Exception exCl ) {}
		    }
Name and version of the database you are using:MySQL 5.x
newId hat leider den Value 0 !? Wo ist denn die DB id die Aktuelle nach dem speichern ?