Hibernate: how to map one-to-many with another database?

I have 2 classes: User and Message.

One user can have several messages.

I.e. this is association one-to-many.

My users table is in first database and the messages table in the second database.

How can I map them?

My users and messages tables mapping:

<hibernate-mapping>
    <class name="com.example.hibernate.User" table="users" lazy="false">
    <id name="xId" type="int" column="xid" >
            <generator class="increment"/>   
    </id>

    <set name="messages" inverse="true" table="messages">
        <key>
            <column name="xsin_id" not-null="true" />
        </key>
        <one-to-many class="com.example.hibernate.Message" />
     </set>     
</class>
</hibernate-mapping>


<hibernate-mapping>
  <class name="com.example.hibernate.Message" table="messages" lazy="false">
       <id name="id" type="int" column="xmsgbox" >
        <generator class="increment"/>     
       </id>

       <many-to-one name="user" class="com.example.hibernate.User">
               <column name="xsin_id" not-null="true" />
           </many-to-one>
   </class>
</hibernate-mapping>

I also have 2 *.cfg.xml files where these classes are mapped.

My test code snipplet:

Session session = HibernateUtilUser.getSession();

String SQL_QUERY ="from User user";
Query query = session.createQuery(SQL_QUERY);
User user = null;
for(Iterator it=query.iterate();it.hasNext();){
    user=(User)it.next();               
    break;
}
Set<Message> messages = user.getMessages();
assertNotNull(messages);

I get an error: Association references unmapped class: com.example.hibernate.Message

P.S. my HibernateUtilUser class:

public class HibernateUtilUser {

    private static SessionFactory sf;
    private static Session session;

    private HibernateUtil() {}

    public static SessionFactory getSessionFactory() {      
        if (sf == null) {
          开发者_开发知识库  sf = new Configuration().configure("hibernateuser.cfg.xml").buildSessionFactory();
        }       
        return sf;      
    }

    public static Session getSession() {
        if (session == null || session.isOpen() == false) {
            session = getSessionFactory().openSession(); 
        }       
        return session;
    }

    public Session openSession() {
        return sf.openSession();
    }

    public static void close(){
    if (sf != null)
        sf.close();
        sf = null;
    }
}

Try giving DB name in table proeprty, like table="[your another DB Name]..messages"

<set name="messages" inverse="true" table="AnotherDB..messages"> 
        <key> 
            <column name="xsin_id" not-null="true" /> 
        </key> 
        <one-to-many class="com.example.hibernate.Message" /> 
     </set>  

This solution seems working link text

You need to use one SessionFactory only. Then, in the mapping files for your classes, use the schema or catalog attributes. For example:

Code:
<class name="Test1" table="Test1" catalog="...">

<class name="Test2" table="Test2" catalog="...">


This of course assumes that the databases lives in the same MySQL server.