Hibernate version:
3.1

Mapping documents:
I am mapping User and Album -> 1 user may have * Albums
I am using a list interface, so I am using the list element and an list-index in my mapping. The pos column is created in the schema.

Here is the user mapping:

<hibernate-mapping
package="de.pixxi.om">

<class name="User" table="User">

<id name="id" type="string" unsaved-value="null" >
<column name="userId" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex"/>
</id>

<property name="username"/>
<property name="password"/>
<property name="verification"/>
<property name="sex"/>
<property name="firstname"/>
<property name="lastname"/>
<property name="email"/>
<property name="birthday" type="date"/>
<property name="newsletterrequested"/>

<list name="albums" table="Album" cascade="all-delete-orphan" outer-join="true" inverse="true">
<key column="userId"/>
<list-index column="pos" base="1"/>
<one-to-many class="Album" />
</list>

</class>

</hibernate-mapping>

And here is the Album (Album has Images, but this is irrelevant)

<hibernate-mapping
package="de.pixxi.om">

<class name="Album" table="Album">

<id name="id" type="string" unsaved-value="null" >
<column name="albumId" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex"/>
</id>


<property name="name"/>

<list name="images" table="Image" cascade="all-delete-orphan" outer-join="true" inverse="true">
<key column="albumId"/>
<list-index column="pos" base="1"/>
<one-to-many class="Image" />
</list>

<many-to-one
name="user"
class="User"
column="userId"
not-null="true"
/>

</class>

</hibernate-mapping>


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

Session session = this.getSession();
Transaction tx = session.beginTransaction();

User user;
Criteria crit = session.createCriteria(User.class);
crit.setFetchMode("albums", FetchMode.JOIN);
crit.add(Expression.eq("username", username));
crit.setMaxResults(1);
List userList = crit.list();
if (userList != null)
log.debug("Anzahl user gefunden: " + userList.size());
if (userList == null || userList.size() < 1) {
log.warn("User not found!");
return null;
} else
user = (User) userList.get(0);

tx.commit();
session.close();

Full stack trace of any exception that occurs:

Note: it is happening in a JSF web app. After creating a user and adding an album, the user is reloaded. While loading, the error occurs because <b>the pos column</b> does not contain an index. it is simply null.... but I don't get why hibernate does not fill out the pos column...

Caused by: javax.faces.el.EvaluationException: Exception while invoking expression #{verificationBean.verify}
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:153)
at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:63)
... 23 more
Caused by: org.hibernate.HibernateException: null index column for collection: de.pixxi.om.User.albums
at org.hibernate.persister.collection.AbstractCollectionPersister.readIndex(AbstractCollectionPersister.java:652)
at org.hibernate.collection.PersistentList.readFrom(PersistentList.java:358)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:994)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:635)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:580)
at org.hibernate.loader.Loader.doQuery(Loader.java:689)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
at org.hibernate.loader.Loader.doList(Loader.java:2145)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
at org.hibernate.loader.Loader.list(Loader.java:2024)
at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1552)
at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)
at de.pixxi.biz.AlbumDelegateImpl.getUser(Unknown Source)
at de.pixxi.model.VerificationBean.verify(Unknown Source)
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:585)
at org.apache.myfaces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:129)
... 24 more

Name and version of the database you are using:
MySQL 5


The generated SQL (show_sql=true):

sorry, don't have it. But the error reason is that the album list cannot be ordered, as the pos column in the Album table is null.

One thing: I am using a typed List<Album> in User. Could this be the reason?

Any help is highly appreciated... thanx a lot!

Cheers
Sven

The first thing to do is to set the pos columns to be NOT NULL. I don't know why list-index doesn't take a not-null attribute, perhaps the schematool always puts NOT NULL on list-index columns. Either way, once that's a not-null column, you'll get an exception any time a row with a null list-index is added, and that'll help you track down the cause of the problem.