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Hibernate version:

3.0

Mapping documents:

<hibernate-mapping package="com.wiag.hdb.model">

<class name="LieferPunktGruppeInfo" table="A10T_LFPGRP_INF">
<composite-id name="id" class="LieferPunktGruppeInfoKey">
<key-property name="lieferPunktGruppeID" column="LFPGRP_LFPGRP" type="java.lang.Long"/>
<key-property name="vertragID" column="LFPGRP_ZO_ID" type="java.lang.Long"/>
<key-property name="typ" column="TYP" type="java.lang.Integer"/>
<key-property name="von" column="VON" type="java.util.Date"/>
<key-property name="za" column="ZA" type="java.lang.Integer"/>
</composite-id>

<timestamp name="aendZm" column="AEND_ZM"/>
<property name="bis" column="BIS" type="java.util.Date" />
<property name="wert" column="WERT" type="java.lang.Long" not-null="true" />
<property name="wertEh" column="WERT_EH" type="java.lang.Long" not-null="true" />
<property name="aendId" column="AEND_ID" type="java.lang.Long" />

</class>

</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:

java.lang.UnsupportedOperationException: cannot perform lookups on timestamps
at org.hibernate.type.TimestampType.getHashCode(TimestampType.java:99)
at org.hibernate.type.AbstractType.getHashCode(AbstractType.java:119)
at org.hibernate.type.ComponentType.getHashCode(ComponentType.java:162)
at org.hibernate.engine.EntityKey.getHashCode(EntityKey.java:68)
at org.hibernate.engine.EntityKey.<init>(EntityKey.java:41)
at org.hibernate.loader.Loader.getKeyFromResultSet(Loader.java:664)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:277)
at org.hibernate.loader.Loader.doQuery(Loader.java:384)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:203)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1344)
at org.hibernate.loader.collection.OneToManyLoader.initialize(OneToManyLoader.java:106)
at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:484)
at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1346)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:170)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:47)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:133)
at test.com.wiag.hdb.dao.TestLieferPunktGruppeDAO.testGetLieferPunktVertragByLieferPunktGruppeKey(TestLieferPunktGruppeDAO.java:80)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at junit.framework.TestCase.runTest(TestCase.java:154)
at junit.framework.TestCase.runBare(TestCase.java:127)
at junit.framework.TestResult$1.protect(TestResult.java:106)
at junit.framework.TestResult.runProtected(TestResult.java:124)
at junit.framework.TestResult.run(TestResult.java:109)
at junit.framework.TestCase.run(TestCase.java:118)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:421)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:305)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:186)

Name and version of the database you are using:

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:



A legacy database used composite business key with a timestamp column. It seems that such a timestamp column as a key column is not supported any more in Hibernate 3.x. Ist there any workaround for this problemm without changing the database schema?

For what is know.

Hibernate takes by default the Hibernate.TIMESTAMP type which do not allow to create a hashCode.
Try setting your column type to Hibernate.DATE.

I use annotatinos so I am not sure if this mapping works, but it should give you a clue.
<property name="your date col">
<type name="DATE" />
</property>

btw: http://www.hibernate.org/hib_docs/v3/reference/en/html/mapping.html#mapping-types-custom

What if I need the time information? I just see no reason when the hashcode of a timestamp can't be calculated?

You are right, my suggestion with DATE strips the time part. If you cant change to CALENDAR the only solution I see is to write your own UserType - this isnt too hard.

See
http://cvs.sourceforge.net/viewcvs.py/joda-time/JodaTimeContrib/src/java/org/joda/time/contrib/hibernate/PersistentDateTime.java
how I have done this for joda-time.

The only problem - if you need it - you still might have is the "nanos" part of the timestamp which is stripped too. For what I know this "nanos" part was the base for the decision to remove the hashCode function for Timestamps.