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hugeride
 Post subject: Help needed on many-to-many implementation!!
PostPosted: Fri Sep 23, 2005 10:55 am 
Newbie

Joined: Thu Aug 18, 2005 12:24 pm
Posts: 11
Hibernate version: 3.1

I have a many-to-many schema ( students and courses ).

Hi. Im getting this exception when trying to list all students:

org.hibernate.PropertyAccessException: exception setting property value with CGLIB (set hibernate.cglib.use_reflection_optimizer=false for more info) setter of br.com.mindsatwork.libraryweb.hibernatebeans.Student.setCourses
at org.hibernate.tuple.PojoTuplizer.setPropertyValuesWithOptimizer(PojoTuplizer.java:217)
at org.hibernate.tuple.PojoTuplizer.setPropertyValues(PojoTuplizer.java:187)
at org.hibernate.persister.entity.BasicEntityPersister.setPropertyValues(BasicEntityPersister.java:2945)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:115)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:791)
at org.hibernate.loader.Loader.doQuery(Loader.java:689)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:221)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1610)
at org.hibernate.loader.entity.EntityLoader.load(EntityLoader.java:117)
at org.hibernate.loader.entity.EntityLoader.load(EntityLoader.java:102)
at org.hibernate.persister.entity.BasicEntityPersister.load(BasicEntityPersister.java:2476)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:358)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:339)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:116)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:78)
at org.hibernate.impl.SessionImpl.immediateLoad(SessionImpl.java:649)
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:60)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:85)
at org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:131)
at br.com.mindsatwork.libraryweb.hibernatebeans.Student$$EnhancerByCGLIB$$11dd15c0.getFirstName(<generated>)
....

My classes are Student and Course. It is a many-to-many schema and my mapping file for classes are :

Student.hbm.xml :

<hibernate-mapping package="xx.xxx.xxxxxxxxx.libraryweb.hibernatebeans">

<class name="Student" table="student">
<id name="id" column="id" type="java.lang.Integer">
<generator class="native"/>
</id>

<property name="firstName" column="first_name" type="java.lang.String" />
<property name="lastName" column="last_name" type="java.lang.String" />
<property name="address" column="address" type="java.lang.String" />
<property name="contact" column="contact" type="java.lang.String" />

<set name="courses" table="college_registrations" inverse="true" cascade="all">
<key column="student_id"/>
<many-to-many column="course_id" class="Course" />
</set>
</class>

</hibernate-mapping>

Couse.hbm.xml :

<hibernate-mapping package="xx.xxx.xxxxxxxxx.libraryweb.hibernatebeans">
<class name="Course" table="course">
<id name="id" column="id" type="java.lang.Integer">
<generator class="native"/>
</id>

<set name="students" table="college_registrations" cascade="all" >
<key column="course_id"/>
<many-to-many column="student_id" class="Student" />
</set>



<property name="name" column="name" type="java.lang.String" />
<property name="prerequisites" column="prerequisites" type="java.lang.String" />
<property name="description" column="description" type="java.lang.String" />
<property name="numberOfCredits" column="credits" type="java.lang.Integer" />
</class>

</hibernate-mapping>

I have only one student and one course at database. The student is registered in the course ( wich is represented by a entry in college_registrations table that maps the many-to-many relation )

When I try to list the students I got the exception below...
Any Idea? Student class has a List of couses inside ( List getCourses, void setCourses( List courses ) ) and Couse class has a List of Students... )

Any Idea? HELP!
thanks
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hugeride
 Post subject:
PostPosted: Fri Sep 23, 2005 12:15 pm 
Newbie

Joined: Thu Aug 18, 2005 12:24 pm
Posts: 11
THE ERROR HAVE BEEN SOLVED! THANKS AND SORRY FOR THE INCONVENIENCE ;)
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totopo
 Post subject: I have a similar problem
PostPosted: Fri Sep 30, 2005 2:33 pm 
Newbie

Joined: Sun Aug 01, 2004 9:57 am
Posts: 4
I have a similar problem, my mappings are like these:

Categories:
Code:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
   <class name="com.artconstructionsystems.dblayer.vobjects.Category" table="category">
      <id name="id" column="category_id" type="long">
         <generator class="native"/>
      </id>
      <property name="name"/>
      <many-to-one name="parentCategory" class="com.artconstructionsystems.dblayer.vobjects.Category" column="parent_id" cascade="all"/>
      <set name="childCategories" table="category" cascade="all" inverse="true">
         <key column="parent_id"/>
         <one-to-many class="com.artconstructionsystems.dblayer.vobjects.Category"/>
      </set>
      <set name="items" table="category_item" cascade="save-update">
         <key column="category_id"/>
         <many-to-many class="com.artconstructionsystems.dblayer.vobjects.Item" column="item_id"/>
      </set>
      
   </class>
</hibernate-mapping>


Items:
Code:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">
<hibernate-mapping>
   <class name="com.artconstructionsystems.dblayer.vobjects.Item" table="item">
      <id name="id" column="item_id" type="long">
         <generator class="native"/>
      </id>
      <property name="itemName" type="text" not-null="true"/>
      <property name="createDate" type="java.util.Date" not-null="true"/>
      <!-- inverse end -->
      <set name="categories" table="category_item" inverse="true" cascade="save-update">
         <key column="item_id"/>
         <many-to-many class="com.artconstructionsystems.dblayer.vobjects.Category" column="category_id"/>
      </set>
   </class>
</hibernate-mapping>


When I delete an item I still have a reference to the category in the category_item table, how to remove the reference in table category_item!!??

I have tried delete-orphan but deletes the orphans in the category table.

Regards

totopo
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totopo
 Post subject: Query
PostPosted: Fri Sep 30, 2005 2:57 pm 
Newbie

Joined: Sun Aug 01, 2004 9:57 am
Posts: 4
and when I try to get all data from table Category using the HQL:

Code:
from Category c, order by category_id,parent_id,name


Code:
Hibernate: select item0_.item_id as item_id0_, item0_.itemName as itemName0_, item0_.createDate as createDate0_ from item item0_ where item0_.item_id=?


Code:
org.springframework.orm.hibernate.HibernateObjectRetrievalFailureException: No row with the given identifier exists: 1, of class: com.artconstructionsystems.dblayer.vobjects.Item; nested exception is net.sf.hibernate.UnresolvableObjectException: No row with the given identifier exists: 1, of class: com.artconstructionsystems.dblayer.vobjects.Item
net.sf.hibernate.UnresolvableObjectException: No row with the given identifier exists: 1, of class: com.artconstructionsystems.dblayer.vobjects.Item
   at net.sf.hibernate.UnresolvableObjectException.throwIfNull(UnresolvableObjectException.java:38)
   at net.sf.hibernate.impl.SessionImpl.internalLoad(SessionImpl.java:1964)
   at net.sf.hibernate.type.ManyToOneType.resolveIdentifier(ManyToOneType.java:69)
   at net.sf.hibernate.type.EntityType.resolveIdentifier(EntityType.java:208)
   at net.sf.hibernate.type.EntityType.nullSafeGet(EntityType.java:130)
   at net.sf.hibernate.collection.AbstractCollectionPersister.readElement(AbstractCollectionPersister.java:365)
   at net.sf.hibernate.collection.Set.readFrom(Set.java:233)
   at net.sf.hibernate.loader.Loader.readCollectionElement(Loader.java:384)
   at net.sf.hibernate.loader.Loader.getRowFromResultSet(Loader.java:240)
   at net.sf.hibernate.loader.Loader.doQuery(Loader.java:285)
   at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:138)
   at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:1020)
   at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:995)
   at net.sf.hibernate.loader.CollectionLoader.initialize(CollectionLoader.java:83)
   at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:288)
   at net.sf.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:3315)
   at net.sf.hibernate.collection.PersistentCollection.forceInitialization(PersistentCollection.java:336)
   at net.sf.hibernate.impl.SessionImpl.initializeNonLazyCollections(SessionImpl.java:3168)
   at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:143)
   at net.sf.hibernate.loader.Loader.doList(Loader.java:1063)
   at net.sf.hibernate.loader.Loader.list(Loader.java:1054)
   at net.sf.hibernate.hql.QueryTranslator.list(QueryTranslator.java:854)
   at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1554)
   at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:49)
   at org.springframework.orm.hibernate.HibernateTemplate$19.doInHibernate(HibernateTemplate.java:647)
   at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:314)
   at org.springframework.orm.hibernate.HibernateTemplate.find(HibernateTemplate.java:633)
   at org.springframework.orm.hibernate.HibernateTemplate.find(HibernateTemplate.java:612)
   at com.artconstructionsystems.dblayer.persistance.DBCategories.getCategories(DBCategories.java:57)
   at com.artconstructionsystems.dblayer.AppTest.testRetrieveCategories(AppTest.java:121)
   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:324)
   at junit.framework.TestCase.runTest(TestCase.java:154)
   at junit.framework.TestCase.runBare(TestCase.java:127)
   at junit.framework.TestResult$1.protect(TestResult.java:106)
   at junit.framework.TestResult.runProtected(TestResult.java:124)
   at junit.framework.TestResult.run(TestResult.java:109)
   at junit.framework.TestCase.run(TestCase.java:118)
   at junit.framework.TestSuite.runTest(TestSuite.java:208)
   at junit.framework.TestSuite.run(TestSuite.java:203)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:436)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:311)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)





or how could I impelement the next query using HQL?

Code:
select * from category,item,category_item where category.category_id = category_item.category_id and category_item.item_id = item.item_id


Please help

Regards

Marco
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totopo
 Post subject: was trivial
PostPosted: Sat Oct 01, 2005 5:09 pm 
Newbie

Joined: Sun Aug 01, 2004 9:57 am
Posts: 4
Ok, was trivial

inverse="true" was on the Category mapping.
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