Hi Jason, I could solve my previous problem. But now i am facing some other problem with many to many relationship tables.
My schema looks as follows: TableA ---> TableC <----- TableB which means there is many to many relationship between TableA & TableB. So i want TableA and TableB primary keys into TableC as foreign key. TableA class looks as follows: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class TableA implements Serializable{ @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key id; ...... @Persistent(defaultFetchGroup="true") private Set<Key> tableB = new HashSet<Key>(); ...... (some getter & setter) TableB class looks as follows: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class TableB implements Serializable{ @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key id; ...... @Persistent(defaultFetchGroup="true") private Set<Key> tableA = new HashSet<Key>(); ...... (some getter & setter) TableC class looks as follows: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class TableC implements Serializable{ @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Key id; @Persistent private TableA tablea; @Persistent private TableB tableb; ..... (some getter & setter) While adding data into TableC i use following code: Query query1 = pm.newQuery(TableA.class); List<TableA> results1 = (List<TableA>) query1.execute(); TableA tableA= results1.get(0); Query query2 = pm.newQuery(TableB.class); List<TableB> results2 = (List<TableB>) query2.execute(); TableB tableB= results2.get(0); tableA.add(tableB); tableB.add(tableA); At this point TableA and TableB values are getting update but while entering data into TableC the problem comes. TableC tableC = new TableC(); tableC.setTableA(tableA); tableC.setTableB(tableB); pm.makePersistent(tableC); --> at this point it gives me "A parent cannot be established or changed once an object has been persisted." Can you please tell me were i am going wrong? Thanks Anita On Sep 15, 3:54 am, "Jason (Google)" <apija...@google.com> wrote: > From the error message, it sounds like the parent isn't getting set > correctly. You'll need to share some of your code in order for me to help > you further -- what does your Release class look like and how are you > persisting it? > > - Jason > > On Sat, Sep 12, 2009 at 4:36 AM, Anita <an...@ensarm.com> wrote: > > > Hi Jason, > > > Our schema looks as follows: > > ProductType 1--------->M Product 1-------->M Release > > > Data is inserting into Release table. But while fetching data from > > release table i am getting following exception: > > > Field com.ensarm.server.domain.Release.products should be able to > > provide a reference to its parent but the entity does not have a > > parent. Did you perhaps try to establish an instance of > > com.ensarm.server.domain.Release as the child of an instance of > > com.ensarm.server.domain.Products after the child had already been > > persisted? > > org.datanucleus.exceptions.NucleusUserException: Field > > com.ensarm.server.domain.Release.products should be able to provide a > > reference to its parent but the entity does not have a parent. Did > > you perhaps try to establish an instance of > > com.ensarm.server.domain.Release as the child of an instance of > > com.ensarm.server.domain.Products after the child had already been > > persisted? > > at > > org.datanucleus.store.appengine.DatastoreRelationFieldManager.lookupParent > > (DatastoreRelationFieldManager.java:302) > > at > > > org.datanucleus.store.appengine.DatastoreRelationFieldManager.fetchRelationField > > (DatastoreRelationFieldManager.java:289) > > at > > org.datanucleus.store.appengine.DatastoreFieldManager.fetchObjectField > > (DatastoreFieldManager.java:271) > > at org.datanucleus.state.AbstractStateManager.replacingObjectField > > (AbstractStateManager.java:1197) > > at com.ensarm.server.domain.Release.jdoReplaceField(Release.java) > > at com.ensarm.server.domain.Release.jdoReplaceFields(Release.java) > > at org.datanucleus.state.JDOStateManagerImpl.replaceFields > > (JDOStateManagerImpl.java:2772) > > at org.datanucleus.state.JDOStateManagerImpl.replaceFields > > (JDOStateManagerImpl.java:2791) > > at > > org.datanucleus.store.appengine.DatastorePersistenceHandler.fetchObject > > (DatastorePersistenceHandler.java:349) > > at org.datanucleus.store.appengine.query.DatastoreQuery.entityToPojo > > (DatastoreQuery.java:384) > > at org.datanucleus.store.appengine.query.DatastoreQuery.entityToPojo > > (DatastoreQuery.java:345) > > at org.datanucleus.store.appengine.query.DatastoreQuery.access$700 > > (DatastoreQuery.java:96) > > at org.datanucleus.store.appengine.query.DatastoreQuery$5.apply > > (DatastoreQuery.java:454) > > at org.datanucleus.store.appengine.query.DatastoreQuery$5.apply > > (DatastoreQuery.java:453) > > at > > org.datanucleus.store.appengine.query.StreamingQueryResult.resolveNext > > (StreamingQueryResult.java:137) > > at org.datanucleus.store.appengine.query.StreamingQueryResult > > $1.computeNext(StreamingQueryResult.java:163) > > at > > org.datanucleus.store.appengine.query.AbstractIterator.tryToComputeNext > > (AbstractIterator.java:132) > > at org.datanucleus.store.appengine.query.AbstractIterator.hasNext > > (AbstractIterator.java:127) > > at org.datanucleus.store.appengine.query.StreamingQueryResult > > $AbstractListIterator.hasNext(StreamingQueryResult.java:229) > > at com.ensarm.server.servlet.GetData.getRelease(GetData.java:87) > > at com.ensarm.server.servlet.GetData.doGet(GetData.java:32) > > at javax.servlet.http.HttpServlet.service(HttpServlet.java:693) > > at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) > > at > > org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java: > > 487) > > at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter > > (ServletHandler.java:1093) > > at > > com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter > > (TransactionCleanupFilter.java:43) > > at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter > > (ServletHandler.java:1084) > > at com.google.appengine.tools.development.StaticFileFilter.doFilter > > (StaticFileFilter.java:124) > > at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter > > (ServletHandler.java:1084) > > at org.mortbay.jetty.servlet.ServletHandler.handle > > (ServletHandler.java:360) > > at org.mortbay.jetty.security.SecurityHandler.handle > > (SecurityHandler.java:216) > > at org.mortbay.jetty.servlet.SessionHandler.handle > > (SessionHandler.java:181) > > at org.mortbay.jetty.handler.ContextHandler.handle > > (ContextHandler.java:712) > > at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java: > > 405) > > at > > com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle > > (DevAppEngineWebAppContext.java:54) > > at org.mortbay.jetty.handler.HandlerWrapper.handle > > (HandlerWrapper.java:139) > > at com.google.appengine.tools.development.JettyContainerService > > $ApiProxyHandler.handle(JettyContainerService.java:313) > > at org.mortbay.jetty.handler.HandlerWrapper.handle > > (HandlerWrapper.java:139) > > at org.mortbay.jetty.Server.handle(Server.java:313) > > at > > org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java: > > 506) > > at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete > > (HttpConnection.java:830) > > at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:514) > > at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211) > > at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381) > > at org.mortbay.io.nio.SelectChannelEndPoint.run > > (SelectChannelEndPoint.java:396) > > at org.mortbay.thread.BoundedThreadPool$PoolThread.run > > (BoundedThreadPool.java:442) > > > What should be done for this problem? > > > Anita --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. 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