// dataprovider for the first db:

_configuration = (new Configuration()).Configure();

// this is what i want ... or something similar
_sessionFactory = _configuration.BuildSessionFactory("firstdb");

_session = _sessionFactory.GetSession();
...

<hibernate-configuration  xmlns="urn:nhibernate-configuration-2.2" >
  <session-factory name="firstdb"> ...  </session-factory>
  <session-factory name="seconddb"> ...  </session-factory>
</hibernate-configuration>

_configuration = (new Configuration()).Configure();

IDictionary<string, string> properties = new Dictionary<string, string>();
         properties.Add("connection.provider", "NHibernate.Connection.DriverConnectionProvider");
         properties.Add("connection.driver_class", "NHibernate.Driver.OracleClientDriver");
         properties.Add("connection.connection_string",
                     "CONNECTION");
         properties.Add("show_sql", "false");
         properties.Add("prepare_sql", "false");
         properties.Add("dialect", "NHibernate.Dialect.Oracle9Dialect");
         properties.Add("use_outer_join", "false");
         properties.Add("query.substitutions", "true 1, false 0, yes 'Y', no 'N'");         
         _configuration .SetProperties(properties);

         _configuration .AddAssembly("BusinessObjectsAssembly");

public static SessionFactory getCustomSessionFactory(String URL,
         String userName, String password) {
      
      String parentURL = cfg.getProperty("hibernate.connection.url");
      String parentUserName = cfg.getProperty("hibernate.connection.username");
      String parentPassword = cfg.getProperty("hibernate.connection.password");
      
      Configuration customCfg = new Configuration();   // configuration must have been already loaded
      try {
         // Solution 1: works but you have to set the original values back in the parent OR else!!!
         //customCfg = cfg;
         
         // Solution 2: works but too slow as it re-creates and loads and tests every config file
         customCfg.configure(CONFIG_FILE_LOCATION);   // slow
         
         // Solution 3: does not work
         // customCfg = (Configuration) BeanUtils.cloneBean(cfg);    // does a shallow copy
         // BeanUtils.copyProperties(customCfg, cfg);
         // does not copy Indexed and mapped properties without getters and setters
      
         customCfg.setProperty("hibernate.connection.url", URL);
         customCfg.setProperty("hibernate.connection.username", userName);
         customCfg.setProperty("hibernate.connection.password", password);
      
         String sessionFactoryJndiName = customCfg
               .getProperty(Environment.SESSION_FACTORY_NAME);
         if (sessionFactoryJndiName != null) {
            customCfg.buildSessionFactory();
            return (SessionFactory) (new InitialContext())
                  .lookup(sessionFactoryJndiName);

         } else {
            return customCfg.buildSessionFactory();
         }

      } catch (Exception e) {
         e.printStackTrace();
         return null;
      }
      finally
      {
                         //  trying to save time by re-using the first configuration as all schemas had the same structure and
                      // and hence the same configuration file configuration would suffice
         // cfg.setProperty("hibernate.connection.url", parentURL);
         // cfg.setProperty("hibernate.connection.username", parentUserName);
         // cfg.setProperty("hibernate.connection.password", parentPassword);
      }
   }