Hello.

I am trying to use Oracle (Oracle 9.2.0.4) sequences with Hibernate (Hibernate 2.1), and I am having trouble. Can anybody help me?

The MAPPING DEFINITION that I have is the following:

[code]<hibernate-mapping>
...
<id name="id" type="long" unsaved-value="null">
<generator class="sequence">
<param name="sequence">WGWCustomer_sequence</param>
</generator>
</id>
...
</hibernate-mapping>[/code]

And the JAVA CODE that I am usind is the following:

[code]// Creates and initializes the Hibernate session factory
try {
hibernateSessionFactory = new Configuration().configure().buildSessionFactory();
} catch (HibernateException e) {
e.printStackTrace();
System.exit(1);
}

// Creates an Hibernate session
try {
hibSession = hibernateSessionFactory.openSession();
tx = hibSession.beginTransaction();
} catch(Exception e) {
e.printStackTrace();
System.exit(1);
}

// Loads new data
try {
// Create a new Customer
WGWCustomer customer = new WGWCustomer();
customer.setId(???); // How to use the seq?
customer.setName("Telefonica");
customer.setDescription("Operador de Telecomunicaciones");
customer.setDomain("www.telefonica.com");
// Persist the new Customer
hibSession.save(customer);
...
}[/code]

Regarding the XML and Java code given above, I have 2 questions:

1.- How should I use the sequence in the Java code? Do I have to use a customer.setId(???) instruction? Something different?

2.- When I execute the Java code I get the exception:

[code]D:\Proyectos\wgw>wgw_initial_data.bat
net.sf.hibernate.MappingException: could not instantiate id generator
at net.sf.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:82)
at net.sf.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:82)
at net.sf.hibernate.persister.AbstractEntityPersister.<init>(AbstractEntityPersister.java:630)
at net.sf.hibernate.persister.EntityPersister.<init>(EntityPersister.java:716)
at net.sf.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:42)
at net.sf.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:137)
at net.sf.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:768)
at es.tid.psstlatam.api.wgw.WGWInitialData.main(WGWInitialData.java:35)
Caused by: net.sf.hibernate.MappingException: Dialect does not support sequences
at net.sf.hibernate.dialect.Dialect.getSequenceNextValString(Dialect.java:319)
at net.sf.hibernate.id.SequenceGenerator.configure(SequenceGenerator.java:62)
at net.sf.hibernate.id.IdentifierGeneratorFactory.create(IdentifierGeneratorFactory.java:78)
... 7 more[/code]

So, it seems there is a problem supporting sequences, but my Dialect (hibernate.dialect net.sf.hibernate.dialect.Oracle9Dialect) clearly supports sequences.

Any idea?


Thank you very much, Manuel.

More information regarding the problem with Oracle sequences:

It seems to me that the Java code:

[code]hibernateSessionFactory = new Configuration().configure().buildSessionFactory(); [/code]
is not fetching the Dialect correctly.

I say this because I have added the following:

[code]try {
hibernateSessionFactory = new Configuration().configure().buildSessionFactory();
dialect = Dialect.getDialect();
System.out.println("Supports seqs? "+dialect.supportsSequences());
} catch (HibernateException e) {
e.printStackTrace();
System.exit(1);
}[/code]

and I get the exception:

[code]net.sf.hibernate.HibernateException: [color=red]The dialect was not set. Set the property hibernate.dialect.[/color]
at net.sf.hibernate.dialect.Dialect.getDialect(Dialect.java:354)
at es.tid.psstlatam.api.wgw.WGWInitialData.main(WGWInitialData.java:39)[/code]

which clearly determines that the Dialect is not beeing set.

My XML configuration file is in the CLASSPATH, and it has the following information:

[code]<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration
PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

<hibernate-configuration>
<session-factory>
<!-- connection to oracle database -->
<property name="hibernate.connection.driver_class">oracle.jdbc.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:@10.95.85.196:1521:GENEVA53</property>
<property name="hibernate.connection.username">wgw</property>
<property name="hibernate.connection.password">wgw</property>
<!-- other properties -->
<property name="hibernate.show_sql">true</property>
<property name="hibernate.dialect">net.sf.hibernate.dialect.Oracle9Dialect</property>
<!-- connection pooling -->
<!-- hibernate provides C3PO connection pooling, but this is not suitable for production envs -->
<property name="hibernate.c3po.min_size">5</property>
<property name="hibernate.c3po.max_size">20</property>
<property name="hibernate.c3po.timeout">1800</property>
<property name="hibernate.c3po.max_statements">50</property>

<!-- Mapping files -->
<mapping resource="WGWAuditTrail.hbm.xml"/>
<mapping resource="WGWCustomer.hbm.xml"/>
...
</session-factory>
</hibernate-configuration>[/code]

I have also tried to do the following in the Java code:

[code]hibernateSessionFactory = new Configuration().configure(new File("<path>\\hibernate.cfg.xml")).buildSessionFactory();[/code]
and I doesn't work either!

Any idea? Thank you, Manuel.

WGWCustomer customer = new WGWCustomer();
customer.setId(???); // How to use the seq?
customer.setName("Telefonica");
customer.setDescription("Operador de Telecomunicaciones");
customer.setDomain("www.telefonica.com");
// Persist the new Customer
hibSession.save(customer);


you do not have to call setId(), it will be done by calling session.save(obj)