Multiple database configuration

dv8 · **Joined:** Wed Nov 30, 2005 10:54 am **Posts:** 13

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Hibernate version: 3.1

Name and version of the database you are using: Oracle 9i2

Hi,

I would like some help (example configuration files, opinions and suggestions) whilst configuring Hibernate to use serveral databases. The current application being developped using Spring / Java and Hibernate must access 3 databases.

How should I configure the hibernate configuration file ? How will my HibernateUtil.java be impacted ?

Thanks.

ramnath · **Posted:** Thu Jan 12, 2006 6:07 am

Here we go,

http://www.mail-archive.com/hibernate-d ... 00834.html

dv8 · **Joined:** Wed Nov 30, 2005 10:54 am **Posts:** 13

Hi thanks for your reply, but i'm not to sure that it works.

Heres my hibernate.cfg.xml :

Code:

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
    <session-factory >

      <!-- local connection properties -->
      <property name="hibernate.connection.url">jdbc:mysql://url/name</property>
      <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
      <property name="hibernate.connection.username">username</property>
      <property name="hibernate.connection.password">password</property>
      <!-- property name="hibernate.connection.pool_size"></property -->

      <!-- dialect for MySQL -->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

        <property name="hibernate.show_sql">false</property>
        <property name="hibernate.use_outer_join">true</property>
        <property name="hibernate.cglib.use_reflection_optimizer">false</property>

      <mapping resource="accesdonnees/Etablissement.hbm" />
      <mapping resource="accesdonnees/Composante.hbm" />
      <mapping resource="accesdonnees/Intervenant.hbm" />
      <mapping resource="accesdonnees/TypeMatiere.hbm" />
      <mapping resource="accesdonnees/Voeu.hbm" />
      <mapping resource="accesdonnees/Service.hbm" />

    </session-factory>
    
    <session-factory >

      <!-- local connection properties -->
      <property name="hibernate.connection.url">jdbc:oracle:thin:@url:1521:name</property>
      <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
      <property name="hibernate.connection.username">username</property>
      <property name="hibernate.connection.password">password</property>
      <!-- property name="hibernate.connection.pool_size"></property -->

      <!-- dialect for Oracle 9 -->
        <property name="dialect">org.hibernate.dialect.Oracle9Dialect</property>

        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.use_outer_join">true</property>

      <mapping resource="Person.hbm" />

    </session-factory>
    
</hibernate-configuration>

Both configurations work when used on their own, but when put together I get the following error :

Quote:

Exception in thread "main" java.lang.ExceptionInInitializerError
at cri.univrennes1.fr.accesdonnees.services.PersonneService.createPersonne(PersonneService.java:23)
at cri.univrennes1.fr.hibernate.TestClient.main(TestClient.java:36)
Caused by: java.lang.RuntimeException: Problème de configuration : problem parsing configuration/hibernate.cfg.xml
at cri.univrennes1.fr.hibernate.HibernateUtil.<clinit>(HibernateUtil.java:18)
... 2 more
Caused by: org.hibernate.HibernateException: problem parsing configuration/hibernate.cfg.xml
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1173)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1112)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1098)
at cri.univrennes1.fr.hibernate.HibernateUtil.<clinit>(HibernateUtil.java:16)
... 2 more
Caused by: org.hibernate.MappingException: invalid configuration
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1169)
... 5 more
Caused by: org.xml.sax.SAXParseException: The content of element type "hibernate-configuration" must match "(session-factory,security?)".
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:236)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:172)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:382)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:316)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.handleEndElement(XMLDTDValidator.java:2048)
at com.sun.org.apache.xerces.internal.impl.dtd.XMLDTDValidator.endElement(XMLDTDValidator.java:932)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanEndElement(XMLNSDocumentScannerImpl.java:719)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1685)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:368)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:834)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:148)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1242)
at org.dom4j.io.SAXReader.read(SAXReader.java:339)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1168)
... 5 more

In the official hibernate documentation, I found the following :

Quote:

Note that this XML configuration uses a different DTD. We configure Hibernate's SessionFactory - a global factory responsible for a particular database. If you have several databases, use several <session-factory> configurations, usually in several configuration files (for easier startup).

Has anybody got any ideas ?

Thanks again.

jwenting · **Joined:** Tue Jan 03, 2006 9:20 am **Posts:** 74

You've not supplied a poolsize. Not sure if that's allowed, maybe you need to supply a number there?

dv8 · **Joined:** Wed Nov 30, 2005 10:54 am **Posts:** 13

Thanks jwenting for your reply, but it doesn't resolve the problem.

rajasaur · **Joined:** Tue Aug 23, 2005 8:52 am **Posts:** 181

You need 2 separate hibernate.xml files , one each for session-factory. The DTD says it all
"The content of element type "hibernate-configuration" must match "(session-factory,security?)
"
That is , a hibernate-configuration can have only one session-factory and one or zero security tags.
Also, if you have multiple sessionFactories in a single file, how you would construct your SessionFactory Object? Which one should hibernate give it for you?

dv8 · **Joined:** Wed Nov 30, 2005 10:54 am **Posts:** 13

Hi rajasaur, thanks for your reply.

What should the names of my configuration files be ? And how should I change my HibernateUtil.java ?

Thanks again.

rajasaur · **Joined:** Tue Aug 23, 2005 8:52 am **Posts:** 181

You can name the xml files whatever you want. hibernate.cfg.xml is the default name that it looks up, but you can have two files, say, hib1.cfg.xml and hib2.cfg.xml and configure your SessionFactories as

Code:

SessionFactory sf1= new Configuration().configure("hib1.cfg.xml").buildSessionFactory();
SessionFactory sf2= new Configuration().configure("hib2.cfg.xml").buildSessionFactory();

ramnath · **Posted:** Thu Jan 12, 2006 7:43 am

So, Cant we have two sessionFactory in a single cfg file?.

Will look in this in detail.

dv8 · **Joined:** Wed Nov 30, 2005 10:54 am **Posts:** 13

Thanks rajasaur, it works.

Does that mean that I have to call the correct sessionFactory when selecting objetcs from each database ?

ramnath · **Posted:** Thu Jan 12, 2006 8:01 am

Yes you have to call the Correct SessionFactory respectively.

wcydiap · **Joined:** Thu Feb 16, 2006 4:45 pm **Posts:** 5

Hi all,

I tried configuring my application to have multiple database access by following the above suggestions, but, was unsuccessful.

I'm using a HibernateUtil class to configure each session. And am doing this at the same time:

Code:

    private static final SessionFactory firstFactory, secondFactory;
    private static Logger logger = Logger.getLogger(HibernateUtil.class.getName());
    static {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            firstFactory = new Configuration().configure("first.cfg.xml").buildSessionFactory();
           secondFactory = new Configuration().configure("second.cfg.xml").buildSessionFactory();
        } catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            logger.error("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getFirstFactory() {
        return firstFactory;
    }    
    public static SessionFactory getSecondFactory() {
        return secondFactory;
    }   

The static block finishes fine for the first one, but, not the second.

There are similar table names in each db and was wondering if this might be the problem. I've given each model class differing package names, but, still get the ExceptionInInitializerError.

Code:

Caused by: java.lang.ExceptionInInitializerError
   at com.util.HibernateUtil.<clinit>(Unknown Source)
   at com.delegate.hbm.HibAnnualExamDel.getAnnualExam(Unknown Source)
   at com.action.AdminExamAction.showExamDetail(Unknown Source)
   ... 49 more
Caused by: java.lang.ClassCastException
   at org.hibernate.tuple.PropertyFactory.buildVersionProperty(PropertyFactory.java:83)
   at org.hibernate.tuple.EntityMetamodel.<init>(EntityMetamodel.java:157)
   at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:412)
   at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:108)
   at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:55)
   at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:215)
   at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1176)
   ... 52 more

Also, I'm attempting to use the firstFactory first. By initializing them at the same time would I somehow be referencing the second one even though I explicitly call getFirstFactory?

Code:

        Session session = HibernateUtil.getFirstFactory().getCurrentSession(); 
        session.beginTransaction();   
       // doesn't look to get past this point
 com.model.hbm.sp.AnnualExam annualExam = (com.model.hbm.sp.AnnualExam) session
                .createQuery("select a from AnnualExam a where a.id = :aid")
                .setParameter("aid", new       Integer(annualExamId)).uniqueResult();    
        
        // find the questions 
        Query q = session.createQuery(
           "from AnnualExamQuestion aeq where aeq.annualExam = :ae");
        List questions = q.setParameter("ae", annualExam).list();        
           annualExam.setAnnualExamQuestions(Collections.synchronizedSet(new            HashSet(questions)));         
                
        session.getTransaction().commit();        

TIA - g

wcydiap · **Joined:** Thu Feb 16, 2006 4:45 pm **Posts:** 5

<strike>sorry, looks like i accidentally imported a wrong class. :)</strike>

a little presumptuous. still getting the same error.

anyone?

Code:

Caused by: java.lang.ClassCastException
   at org.hibernate.tuple.PropertyFactory.buildVersionProperty(PropertyFactory.java:83)
   at org.hibernate.tuple.EntityMetamodel.<init>(EntityMetamodel.java:157)
   at org.hibernate.persister.entity.AbstractEntityPersister.<init>(AbstractEntityPersister.java:412)
   at org.hibernate.persister.entity.SingleTableEntityPersister.<init>(SingleTableEntityPersister.java:108)
   at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:55)
   at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:215)
   at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1176)
   ... 52 more

Thanks again.

khoyendra · **Joined:** Sat Jul 30, 2011 3:14 am **Posts:** 5

Thanks rajasaur its working fine for me.
I have two separate config file in for two diff databases and I am using two diff "SessionFactory" object for this like -

Code:

SessionFactory sf1= new Configuration().configure("hib1.cfg.xml").buildSessionFactory();
SessionFactory sf2= new Configuration().configure("hib2.cfg.xml").buildSessionFactory();

and its working fine.