Hibernate: unique leads to exception

[Kata Franciscan]

Hi,
I have a DB table containing names which should be unique. My name class looks (partly) like this:

@Id @GeneratedValue(strategy=GenerationType.AUTO)
private Long id;

@Column(unique=true, nullable=false) 
private String name;

However, if I now try to insert a new name into the db:
HibernateTemplate org.springframework.orm.hibernate3.support.HibernateDaoSupport.getHibernateTemplate().saveOrUpdate(nameObject);

I see an exception if the name is already in the database:

08/12/09 17:25:37 ERROR util.JDBCExceptionReporter: ERROR: duplicate key violates unique constraint "personalnames_name_key"
08/12/09 17:25:37 ERROR def.AbstractFlushingEventListener: Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266)
at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167)
at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
at org.springframework.orm.hibernate3.HibernateAccessor.flushIfNecessary(HibernateAccessor.java:390)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:375)
at org.springframework.orm.hibernate3.HibernateTemplate.saveOrUpdate(HibernateTemplate.java:699)
at hibernate.NameDaoImpl.save(NameDaoImpl.java:51)
at hibernate.NameDaoImpl.saveByName(NameDaoImpl.java:60)
at data.NameManipulator.saveByString(NameManipulator.java:52)    

Can anyone here tell me what is wrong? I am a newbie containing Annotations, Hibernate, PostgreSQL and Spring, so the problem might be anywhere ...

[Emmanuel Bernard]

You are not doing anything wrong. That's how it's suppose to work.