Hibernate: 3.1.1
Annotations: 3.1 beta8
OS: Windows XP
Database: MySQL 5.x

Table Message
messageId
parentMessageId

public class Message
{
Message getParentMessage(){...}
}

...

select {m.*} from Message

gives a "More than one Row with the same identifier"...removing getParentMessage() from Message fixed the problem.

Does Hibernate support "self-referencing" like above?

yes why should it not.

Yeah, why should it not work? It just does not work :)

Here is the query trace:

select * from Message m

select * from Message message0_ left outer join Message message1_ on message0_.messageOid=message1_.rootMessageOid where message0_.rootMessageOid=?

org.hibernate.HibernateException: More than one row with the given identifier was found: Message@ff665a, for class: Message
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:135)
at org.hibernate.loader.entity.EntityLoader.loadByUniqueKey(EntityLoader.java:85)
at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:1522)
at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:365)
at org.hibernate.type.EntityType.resolve(EntityType.java:306)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:113)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:842)
at org.hibernate.loader.Loader.doQuery(Loader.java:717)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.doList(Loader.java:2150)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
at org.hibernate.loader.Loader.list(Loader.java:2024)
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:117)
at org.hibernate.impl.SessionImpl.listCustomQuery(SessionImpl.java:1672)
at org.hibernate.impl.AbstractSessionImpl.list(AbstractSessionImpl.java:147)
at org.hibernate.impl.SQLQueryImpl.list(SQLQueryImpl.java:169)

are you sure that is the query you run ? "select * from Message m" ? and do you do it through createSQLQuery().list() ?

anyways somehow your query or simply the database contains the same id for more than one row....have you chekked you data?

Well, here is the exact query:

2006-02-13 22:00:21,375 DEBUG [ROOT] (HibernateFuncs.java:75) - SQLQueryImpl(select {m.*} from Message m where category=:p1 order by dateTime desc)

It is through createSQLQuery().list()...

messageOid is the PK for Message, so yeah, I am still scratching my head. Is it possible for Hibernate to log the offending object and its id?

yes: More than one row with the given identifier was found: Message@ff665a, for class: Message

it does not include the id by default, but if you added that in the to-string then it would work.

I found the problem. Here is the correct annotation:

@JoinColumn(name="rootMessageOid", referencedColumnName="messageOid", insertable=false, updatable=false)

Previously, I had the following ERRONEOUS annotation:

@JoinColumn(name="messageOid", referencedColumnName="rootMessageOid", insertable=false, updatable=false)