Hello Hibernate Community !

Hopefully you can help me with a problem. I am writing an electronic flightlog and i have a problem with a many-to-one relation.
It seems that i get the same identifier twice from the hilo table. but i don't know why :(
I get the exception mentioned below.

Thanks for your help in advance!!

Hibernate version:
3.0

Mapping documents:
<hibernate-mapping>
<class name="com.martkoch.flightlog.model.Pilot" table="person" catalog="flightlog">
<id name="idPerson" type="integer">
<column name="id_person" />
<generator class="org.hibernate.id.TableHiLoGenerator">
<param name="table">hibernate_key</param>
<param name="column">next_hi</param>
</generator>
</id>
<property name="firstname" type="string">
<column name="firstname" length="45" not-null="true" />
</property>
<property name="lastname" type="string">
<column name="lastname" length="45" not-null="true" />
</property>
<property name="licenseNumber" type="integer">
<column name="license_number" not-null="true" />
</property>
<property name="licenseValidity" type="timestamp">
<column name="license_validity" length="19" not-null="true" />
</property>

<one-to-one name="flightlog"/>

</class>
</hibernate-mapping>

<hibernate-mapping>
<class name="com.martkoch.flightlog.model.Flightlog" table="flightlog" catalog="flightlog">
<id name="idFlightlog" column="id_person" >
<generator class="foreign">
<param name="property">pilot</param>
</generator>
</id>

<one-to-one name="pilot"
constrained="true" />

<property name="startDate" type="timestamp">
<column name="start_date" length="19" not-null="true" />
</property>
<property name="name" type="string">
<column name="name" length="45" not-null="true" />
</property>

<set name="flights" cascade="all">
<key column="id_flight"/>
<one-to-many class="com.martkoch.flightlog.model.Flight"/>
</set>

</class>
</hibernate-mapping>


<hibernate-mapping>
<class name="com.martkoch.flightlog.model.Flight" table="flight" catalog="flightlog">
<id name="idFlight" type="integer">
<column name="id_flight" unique="true"/>
<generator class="org.hibernate.id.TableHiLoGenerator">
<param name="table">hibernate_key</param>
<param name="column">next_hi</param>
</generator>
</id>
<property name="starttime" type="timestamp">
<column name="starttime" length="19" not-null="true" />
</property>
<property name="stoptime" type="timestamp">
<column name="stoptime" length="19" not-null="true" />
</property>
<property name="comment" type="string">
<column name="comment" length="65535" not-null="true" />
</property>

<many-to-one name="flightlog"
column="id_flightlog"
class="com.martkoch.flightlog.model.Flightlog"/>

<property name="nubmerLandings" type="integer">
<column name="number_landings" not-null="true" />
</property>

</class>
</hibernate-mapping>




Code between sessionFactory.openSession() and session.close():
Transaction myTrans = mySession.beginTransaction();

Pilot pilot = new Pilot();
pilot.setFirstname("Martin");
pilot.setLastname("Koch");
pilot.setLicenseNumber(new Integer(12280));
pilot.setLicenseValidity(new Date());

Flightlog myLog = new Flightlog();
myLog.setPilot(pilot);
myLog.setName("Martins FlightLog");
myLog.setStartDate(new Date());

Flight firstFlight = new Flight();
firstFlight.setFlightlog(myLog);
firstFlight.setStarttime(new Date());
firstFlight.setStoptime(new Date());
firstFlight.setComment("First flight");
firstFlight.setNubmerLandings(new Integer(3));

Flight secondFlight = new Flight();
secondFlight.setFlightlog(myLog);
secondFlight.setStarttime(new Date());
secondFlight.setStoptime(new Date());
secondFlight.setComment("Second flight");
secondFlight.setNubmerLandings(new Integer(4));

Set flights = new HashSet();
flights.add(firstFlight);
flights.add(secondFlight);

myLog.setFlights(flights);

mySession.save(myLog);
mySession.flush();

myTrans.commit();


Full stack trace of any exception that occurs:
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
at org.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:74)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:181)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:226)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:140)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:730)
at com.martkoch.flightlog.test.MyTest.main(MyTest.java:65)
Caused by: java.sql.BatchUpdateException: Duplicate entry '1114112' for key 1
at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1566)
at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:57)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:174)

Name and version of the database you are using:
MySQL 5.0