6 Replies Latest reply on Oct 8, 2010 4:11 AM by Nicole Schweighardt

    ManyToMany bidirectional - inverse side does not load the complete collection

    Nicole Schweighardt Novice

      Hi

       

      I read a lot about eager and lazy fetching and so on but for this case I could not find a solution.

       

      I have a relationship between 'appointment' and 'offer'. An appointment has a list with offers, an offer has a list with appointments. Offer is the owner side.

       

      @Entity
      public class Offer implements Serializable{
          
          @Id
          @GeneratedValue(strategy = GenerationType.AUTO)
          private Long id;
          
          ...
          
          //bidirectional
          //Appointments that are in the offer
          @ManyToMany(fetch=FetchType.EAGER)
          @IndexColumn(name="INDEX_COL")
          private List<Appointment> appointments = new ArrayList<Appointment>();
      
      ...}
      

       

      @Entity
      public class Appointment implements Serializable{
          @Id
          @GeneratedValue(strategy = GenerationType.AUTO)
          private Long id;
          private String title;
          private String description;
          
      
          //unidirektional
          @ManyToOne
          @JoinColumn(name="instructor")
          private CmtUser instructor;
          ...
          //bidirektional
          @ManyToMany(fetch=FetchType.EAGER,mappedBy="appointments") 
          @IndexColumn(name="INDEX_COL")
          private List<Offer> offers= new ArrayList<Offer>();
         ...}
      

       

      If I load an offer from my database in my sessionbean 'OfferHandler', the list with the appointments is fully loaded. (see picture 1) (I tested it with the debugger to look into the collections in the sessionbean, too, not only with my web layer)

       

      public List<Offer> getOffersForInstructor(Long instructorId) {
              try{
                  Query q = em.createQuery("SELECT a from Offer a " +
                          "WHERE a.instructor.id = :instructorId ");
                  q.setParameter("instructorId",instructorId);
      
                  List<Offer> offers =    (List<Offer>) q.getResultList();
                  return offers ;
              }
              catch(EntityNotFoundException ex){}
              return null;
          }
      

       

      But on the other side if I try to load some appointments from my database the collection with the offers only contains the last saved offer! (see picture 2)

       

      public List<Appointment> getFreeAppointments(Long instructorId) {
              
              try{
                  Query q = em.createQuery("SELECT a from Appointment a " +
                          "WHERE a.instructor.id = :instructorId AND " +
                          "a.accepted  =:false ");
                  q.setParameter("instructorId",instructorId);
                  q.setParameter("false",false);
                  
                  List<Appointment> appointments =    (List<Appointment>) q.getResultList();
              
                  return appointments;
      }
      

       

      In the database there is an jointable with the right entries:

      f. example: (the first offer contains the first appointment, the second offer contains both appointments)

       

      offers_id          appointments_id     INDEX_COL
      1                    1                  0
      2                    1                  0
      2                    2                  1
      

       

      I hope someone can help. I tested a lot to force loading the collection. f.example refreshing the appointments or loading the offers in the appointments with appointment.offers.size().

       

      Thank you a lot

      Nicki