problems with many-to-one one-to-many mapping

_hypernate_ · **Joined:** Fri Jan 05, 2007 9:40 pm **Posts:** 3

Hi All !

I'm struggling with a persistence problem since 3 days. I can persist normal bean classes to the database, but a (parent-child relation) many-to-one one-to-many mapping doesn't work.
I have tried many things, read the documentation and examples, but the problem is still there. I have to classes called

Quote:

Order

and

Quote:

OrderPosition

.
I have defined two mapping files

Quote:

Order.hbm.xml

and

Quote:

OrderPosition.hbm.xml

.

I try in a servlet to insert a order into the database, which causes an exception. See below the defitions of the classes and mapping files and the error log.
I'm using

Hibernate 3.2, hsqldb 1.8.0.7 under eclipse 3.2 on windows.

Code:

<hibernate-mapping>
    <class name="model.OrderPosition" table="ORDERPOSITION">
        <id name="id" type="java.lang.Long">
            <column name="ORDERPOSITION_ID" />
            <generator class="native"></generator>
        </id>
        <property name="number" type="java.lang.String">
            <column name="number" not-null="true" unique="true" />
        </property>
        <property name="note" type="java.lang.String">
            <column name="note" />
        </property>
        <property name="quantity" type="java.lang.Long">
            <column name="quantity" />
        </property>
        <property name="price" type="java.lang.Double">
            <column name="price" />
        </property>
        <many-to-one name="order" class="model.Order">
            <column name="ORDER_ID" not-null="true" />
        </many-to-one>
    </class>
</hibernate-mapping>

Code:

<hibernate-mapping>
    <class name="model.Order" table="ORDER">
        <id name="id" type="java.lang.Long">
            <column name="ORDER_ID" />
            <generator class="native"></generator>
        </id>
        <property name="number" type="java.lang.String">
            <column name="number" not-null="true" unique="true" />
        </property>
        <property name="orderDate" type="timestamp">
            <column name="ORDER_DATE" />
        </property>
       <set name="positions" inverse="true" cascade="all">
            <key>
                <column name="ORDER_ID" />
            </key>
            <one-to-many class="model.OrderPosition" />
        </set>
    </class>
</hibernate-mapping>

Code:

public class OrderPosition {
   private Long id;
        private String number;
   private String note;
   private Long quantity;
   private Double price;

       public String getNote() {
      return note;
   }

   public void setNote(String note) {
      this.note = note;
   }

   public String getNumber() {
      return number;
   }

   public void setNumber(String number) {
      this.number = number;
   }
   
        public Double getPrice() {
      return price;
   }

   public void setPrice(Double price) {
      this.price = price;
   }
       
       public Long getQuantity() {
      return quantity;
   }

   public void setQuantity(Long quantity) {
      this.quantity = quantity;
   }
}

Code:

public class Order {

   private Long id;
   private String number = null;
   private Set positions = new HashSet();
   private Date orderDate = null;
   
   public Long getId() {
      return id;
   }

   public void setId(Long id) {
      this.id = id;
   }
   
   public void addPosition(OrderPosition pos) {
       pos.setOrder(this);
       positions.add(pos);
   }
   
   public String getNumber() {
      return number;
   }

   public void setNumber(String number) {
      this.number = number;
   }

   public Set getPositions() {
      return positions;
   }

   public void setPositions(Set positions) {
      this.positions = positions;
   }

   public Date getOrderDate() {
      return orderDate;
   }

   public void setOrderDate(Date orderDate) {
      this.orderDate = orderDate;
   }

}

Code:

public class OrderServlet extends HttpServlet {

   public void doPost(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {
      String action = request.getParameter("action");

      if (action != null && action.trim().length() > 0) {
         Session hSession = HibernateUtil.getSession();

         try {
            hSession.beginTransaction();

            action = action.trim();

            if (action.equalsIgnoreCase("insert")) {
               saveOrder(hSession, request);
            } else if (action.equalsIgnoreCase("update")) {
               updateOrder(hSession, request);
            }

            hSession.getTransaction().commit();
            
            // response
            response.setContentType("text/xml");
            response.setHeader("Cache-Control", "no-cache");
            response.getWriter().write(
                  "Order has been inserted successfully.");

         } catch (Exception exc) {
            System.out.println("Error: " + exc.getMessage());
            exc.printStackTrace();

            Transaction tx = hSession.getTransaction();
            if (tx != null)
               tx.rollback();
            throw new ServletException(exc);
         }
      }
   }

   private void saveOrder(Session session, HttpServletRequest request)
         throws Exception {
      
      try {
         Order order = new Order();
         order.setNumber("A1"); 
         order.setOrderDate(new Date());
         
                        // Code to retrieve postions from request
         ArrayList positions = ...
         
         
         for (int i = 0; i < positions.length(); i++) {
            
            OrderPosition pos = new OrderPosition();
            // Code to init position
            // ...
                                // position is initialized

            order.addPosition(pos);
         }
         session.save(order); 
         session.flush();
         
      } catch (Exception exc) {
         System.out.println("Exception in saveOrder(): "
               + exc.getMessage());
         throw exc;
      }

   }

}

Finally the occured exceptions:

Code:

03:14:14,981 ERROR [OrderServlet]:253 - Servlet.service() for servlet OrderServlet threw exception
org.hibernate.exception.SQLGrammarException: could not insert: [model.Order]
   at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:67)
   at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
   at org.hibernate.id.insert.AbstractSelectingDelegate.performInsert(AbstractSelectingDelegate.java:40)
   at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2108)
   at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2588)
   at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:48)
   at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:248)
   at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:290)
   at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:180)
   at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:108)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
   at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
   at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
   at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:535)
   at org.hibernate.impl.SessionImpl.save(SessionImpl.java:523)
   at org.hibernate.impl.SessionImpl.save(SessionImpl.java:519)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:301)
   at $Proxy0.save(Unknown Source)
   at controller.OrderServlet.saveOrder(OrderServlet.java:99)
   at controller.OrderServlet.doPost(OrderServlet.java:48)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
   at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
   at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
   at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
   at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
   at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
   at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
   at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
   at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
   at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
   at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
   at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
   at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
   at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
   at java.lang.Thread.run(Thread.java:595)
Caused by: java.sql.SQLException: Unexpected token: ORDER in statement [insert into ORDER (ORDER_ID, number, ORDER_DATE) values (null, ?, ?)]
   at org.hsqldb.jdbc.Util.throwError(Unknown Source)
   at org.hsqldb.jdbc.jdbcPreparedStatement.<init>(Unknown Source)
   at org.hsqldb.jdbc.jdbcConnection.prepareStatement(Unknown Source)
   at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:497)
   at org.hibernate.jdbc.AbstractBatcher.prepareStatement(AbstractBatcher.java:94)
   at org.hibernate.id.insert.AbstractSelectingDelegate.performInsert(AbstractSelectingDelegate.java:30)
   ... 39 more

Thanks for any suggestions.

RichK · **Joined:** Sat Jan 06, 2007 4:17 am **Posts:** 1

Try a different table name instead of "Order" (reserved word)

_hypernate_ · **Joined:** Fri Jan 05, 2007 9:40 pm **Posts:** 3

Thank you for your answer.

I changed the table name from ORDER to ORDERTABLE, but i now get this exception:

Code:

Caused by: java.sql.SQLException: Table not found in statement [insert into ORDERTABLE (ORDER_ID, number, ORDER_DATE) values (null, ?, ?)]

I don't understand this error, because hibernate should create the table automatically like it does with other beans (Yes, the table doesn't exist yet).

Even though the hibernate.cfg.xml file contains this rule:

Code:

Any suggestions?

batmat · **Posted:** Sat Jan 06, 2007 9:36 am

I think this is a pitty SchemaUpdate does not check the given value, and then throws an exception if the value is not one of the allowed values.

In fact, true does not exist for the hbm2ddl.auto property, see http://www.hibernate.org/hib_docs/v3/re ... properties :

Quote:

Automatically validate or export schema DDL to the database when the SessionFactory is created. With create-drop, the database schema will be dropped when the SessionFactory is closed explicitly.

eg. validate | update | create | create-drop

Maybe a bug report could be done for this, or at least something like an enhancement request?

wookie2u · **Posted:** Sat Jan 06, 2007 9:41 am

_hypernate_ wrote:

Even though the hibernate.cfg.xml file contains this rule:

Code:

Any suggestions?

... umm are you sure that hbm2ddl.auto isn't commented out in the xml... it's a mistake I made once ... or twice.

Keith.

_hypernate_ · **Joined:** Fri Jan 05, 2007 9:40 pm **Posts:** 3

Yes, you're right batmat. I've used

Quote:

create

instead of

Quote:

true

as value for

Quote:

hbm2ddl.auto

.
Now everything works fine.
Yes, it would make sense to allow true as valid value for hbm2ddl.auto.

Thank you all for constructive suggestion.

wookie2u · **Posted:** Sun Jan 07, 2007 2:16 am

By Goerge robin, I think he's got it.