Updating when it should be inserting

mgreer · **Posted:** Thu Feb 12, 2004 6:56 pm

I have a class Assignment, whose id is a long with unsaved-value of 0. I explicitly set the id to 0 when a new class is created. However, when I saveOrUpdate a new Assignment, is tries to update a row, and then returns a "Batch update row count wrong: 0" error.

Mapping:

Code:

<hibernate-mapping package="com.martin.model" >
    <class name="Assignment" table="assignments">
        
        <id name="id" column="id" type="long" unsaved-value="0">
         <generator class="sequence">
                <param name="sequence">assignments_id_seq</param>
           </generator>
        </id>

      <property name="sequenceNumber" type="int" column="sequence_number" not-null="false" unique="false" />
      <property name="minimumScore" type="java.lang.Integer" column="minimum_score" not-null="false" unique="false" />
      <property name="quickStudy" type="boolean" column="quick_study" not-null="true" unique="false" />
      <property name="master" type="boolean" column="master" not-null="true" unique="false" />
      <property name="test" type="boolean" column="test" not-null="true" unique="false" />

      <many-to-one name="course" class="Course" column="course_id" /> 

      <set name="units" table="assignment_unit_mapping" lazy="true">
         <key column="assignment_id"/> 
         <many-to-many column="unit_id" class="Unit"/> 
      </set> 
 
       <!--inverse="true" means that Homework is responsible for the relation-->
       <set name="homework" inverse="true" lazy="true">
          <key column="assignment_id"/>
          <one-to-many class="Homework"/>
      </set> 
   </class>

Save Code:

Code:

      assignment.setUnits(unitSet);
      assignment.setQuickStudy( quickStudy );
      assignment.setMaster(master);
      assignment.setTest(test);
      course = (Course)get("course");
      assignment.setCourse(course);
      log.info("-  saving assignment: "+assignment);
      assignmentDAO.saveOrUpdate(assignment);
      log.info("- Assignment saved.");

I am using an interceptor with Webwork, which closes and flushes the session after the view is rendered, so that code is not here.
Any help? I have searched the forums and documentation, and am still confused as to why the unsaved-value=0 is not respected. If I print out the id of the new Assignment before saving it, it is 0, so I know it should get inserted, not updated.

The Error:

Code:

Hibernate: update assignments set sequence_number=?, minimum_score=?, quick_study=?, master=?, test=?, course_id=? where id=?
Feb 12, 2004 5:48:45 PM net.sf.hibernate.impl.SessionImpl execute
SEVERE: Could not synchronize database state with session
net.sf.hibernate.HibernateException: Batch update row count wrong: 0

hibernateuser · **Joined:** Tue Feb 10, 2004 12:03 am **Posts:** 16

refere this link

http://www.hibernate.org/74.html#A27

michael · **Posted:** Thu Feb 12, 2004 7:05 pm

Please show us more of your calling code ...

mgreer · **Posted:** Thu Feb 12, 2004 11:45 pm

Thank you for your responses.
Whole saving method:

Code:

   public String go() throws HibernateException {
      String result = INPUT;
      
      AssignmentDAO assignmentDAO = new AssignmentDAO();
      assignmentDAO.initialize(getSession());
      assignment = (Assignment)get("assignment");

      getSession().update(assignment);
      assignment.setMinimumScore( this.minimumScore );
      
      UnitDAO unitDAO = new UnitDAO();
      unitDAO.initialize(getSession());
      List units = unitDAO.findByIds( unitIds );
      Set unitSet = new HashSet();
      unitSet.addAll(units);
      
      assignment.setUnits(unitSet);
      assignment.setQuickStudy( quickStudy );
      assignment.setMaster(master);
      assignment.setTest(test);

      course = (Course)get("course");
      assignment.setCourse(course);
      log.info("-  saving assignment: "+assignment);
      assignmentDAO.saveOrUpdate(assignment);
      log.info("- Assignment saved.");
      result = SUCCESS;
      return result;
   }

As you can see, the assignment is retrieved from the session - get("assignment"). The code where it is placed into the session (HTTPsession, not Hibernate session):

Code:

   public String go() throws HibernateException {
      assignment = new Assignment();
      course = (Course)get("course");
      assignment.setCourse(course);
          assignment.setSequenceNumber(course.getAssignments().size() + 1);
      set("assignment", assignment);
      return SUCCESS;
   }

The code called in AssignmentDAO:

Code:

   public void saveOrUpdate( Object obj ) throws HibernateException {
      Session s = null;
      s = getSession();
      saveOrUpdate( obj, s);
   }

Thanks to the previous submitter for their reference to the FAQ, but I assure you I have already read it and the thread it came form. Indeed, it was reading that which lead me to post, since my situation regarding this error seemed to differ from theirs. The difference is that my unsaved-value is set to 0 for id, and the class sets the id to 0 when a new one is created, yet Hibernate updates instead of inserts. Somehow my object is not considered new, and therein my troubles began...

thanks!
Michael

emmanuel · **Posted:** Fri Feb 13, 2004 4:17 am

Do it again with batch_size=0 and have a look at the debug logs

mgreer · **Posted:** Fri Feb 13, 2004 10:25 am

I seem to have solved it, although to be honest I could not tell you how. The main change is that I circumvented my DAOs and callled getSession().saveOrUpdate(assignment) directly in the class. Somehow, the problem is in there. So much for layering.
Thanks to all, I wish I could be more specific about how this got solved.
-Michael