Hibernate version: hibernate-3.0beta4b

A part of my mapping document :

<class name="Med" table="med">
<id name="SQLId" column="msl_id" type="long" unsaved-value="null">
<generator class="native"/>
</id>
<bag name="attributes" table="attribute" cascade="all,delete-orphan">
<key column="msl_id" not-null="true"/>
<one-to-many class="Med$Attribute"/>
</bag>
</class>


I've the following error, which disappears if i remove 'not-null="true"' on the key element; any idea ?

524 [main] DEBUG org.hibernate.util.DTDEntityResolver - found http://hibernate.sourceforge.net/hibern ... ng-3.0.dtd in classpath
742 [main] ERROR org.hibernate.util.XMLHelper - Error parsing XML: XML InputStream(18) Attribute "not-null" must be declared for element type "key".

Apparently you are pulling an out-of-date version of the DTD from somewhere.

Yes, i loaded the dtd from hibernate3-beta3.jar, thx.