Hello,
Is it possible to define more than one primary key in the .hbm.xml file:
this is a part of this file that i use but i dosn't work:

<class name="beans.MetaData" table="UEPS1.METADATA">
<id name="contentId" type="long">
<column name="CONTENTID" sql-type="number" not-null="true"/>
<generator class="native"/>
</id>


<id name="serverId" type="int">
<column name="SERVERID" sql-type="number" not-null="true"/>
<generator class="native"/>
</id>

<property name="name" type="string">
<column name="NAME" sql-type="varchar2" />

</property>
<property name="value" type="string">
<column name="VALUE" sql-type="varchar2" />
</property>

</class>

Read the composite key section of the manual:
http://www.hibernate.org/hib_docs/reference/html/or-mapping.html#or-mapping-s1-4b