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Please help me solve this problem.
I recently participated in a project.I use hibernate as it is a very excellent
option in handling persistence layer.However,I encountered a problem whcih has already bothered me for two days.Here is my problem:
The project is developing an online test system.The database system I use is Oracle 9i.I created two tables,one is TESTRECORD and the other is
REVIEW.Scriplets are:
TESTRECORD table
CREATE TABLE TESTRECORD
(
T_ID VARCHAR2(64 BYTE) NOT NULL,
SUB_ID VARCHAR2(64 BYTE) NOT NULL,
T_SCORE NUMBER(38) DEFAULT 0,
T_DURATION NUMBER(38),
STUDENT_ID NUMBER(38) NOT NULL,
RV_OPTION NUMBER(3) DEFAULT 0 NOT NULL,
RV_TEACHER_ID NUMBER(38),
CREATE_TIME TIMESTAMP(6) NOT NULL,
LAST_UPDATE_TIME TIMESTAMP(6)
)
CREATE UNIQUE INDEX PK8 ON TESTRECORD
(T_ID)
ALTER TABLE TESTRECORD ADD (
CONSTRAINT PK8 PRIMARY KEY (T_ID)

REVIEW table:
CREATE TABLE REVIEW
(
RV_ID VARCHAR2(64 BYTE) NOT NULL,
T_ID VARCHAR2(64 BYTE) NOT NULL,
RV_CONTENT VARCHAR2(2000 BYTE) NOT NULL,
TEACHER_ID NUMBER(38),
CREATE_TIME TIMESTAMP(6) NOT NULL,
LAST_UPDATE_TIME TIMESTAMP(6)
)
CREATE UNIQUE INDEX PK9 ON REVIEW
(RV_ID)
CREATE INDEX REVIEW_TESTRECORD ON REVIEW
(T_ID)
ALTER TABLE REVIEW ADD (
CONSTRAINT PK9 PRIMARY KEY (RV_ID)

ALTER TABLE REVIEW ADD (
CONSTRAINT REVIEW_TESTRECORD FOREIGN KEY (T_ID)
REFERENCES TESTRECORD (T_ID)
ON DELETE CASCADE);
Hibernate version:
tomcat+hibernate-2.1
Mapping documents:
Review.hbm.xml
<hibernate-mapping package="com.negrid.onlinetest.hibernate.persistence">

<class name="Review" table="REVIEW">
<id name="id" column="RV_ID " type="java.lang.String">
<generator class="assigned"/>
</id>

<property name="content" column="RV_CONTENT" type="java.lang.String" not-null="true" />
<property name="teacherId" column="TEACHER_ID" type="java.lang.Long" />
<property name="createTime" column="CREATE_TIME" type="java.util.Date" not-null="true" />
<property name="lastUpdateTime" column="LAST_UPDATE_TIME" type="java.util.Date" />

<many-to-one name="testRecord" column="T_ID" class="TestRecord" not-null="true" cascade="all" />
</class>

</hibernate-mapping>

TestRecord.hbm.xml
<hibernate-mapping package="com.negrid.onlinetest.hibernate.persistence">

<class name="TestRecord" table="TESTRECORD">
<id name="id" column="T_ID" type="java.lang.String" unsaved-value="id-value">
<generator class="assigned"/>
</id>

<property name="score" column="T_SCORE" type="java.lang.Long" />
<property name="time" column="T_DURATION" type="java.lang.Long" />
<property name="studentId" column="STUDENT_ID" type="java.lang.Long" not-null="true" />
<property name="rvOption" column="RV_OPTION" type="java.lang.Short" />
<property name="teacherId" column="RV_TEACHER_ID" type="java.lang.Long" />
<property name="createTime" column="CREATE_TIME" type="java.util.Date" not-null="true" />
<property name="lastUpdateTime" column="LAST_UPDATE_TIME" type="java.util.Date" />

<set name="reviews"
order-by="RV_ID asc"
lazy="true"
inverse="true"
cascade="all-delete-orphan">
<key column="T_ID" />
<one-to-many class="Review" />
</set>


</class>

</hibernate-mapping>

Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:
Hibernate: select reviews0_.T_ID as T_ID__, reviews0_.RV_ID as RV_ID __, review
s0_.RV_ID as RV_ID 0_, reviews0_.RV_CONTENT as RV_CONTENT0_, reviews0_.TEACHER_
ID as TEACHER_ID0_, reviews0_.CREATE_TIME as CREATE_T4_0_, reviews0_.LAST_UPDATE
_TIME as LAST_UPD5_0_, reviews0_.T_ID as T_ID0_ from REVIEW reviews0_ where revi
ews0_.T_ID=? order by reviews0_.RV_ID asc
net.sf.hibernate.exception.GenericJDBCException: could not initialize collection
: [com.negrid.onlinetest.hibernate.persistence.TestRecord.reviews#UESTC50]
at net.sf.hibernate.exception.ErrorCodeConverter.handledNonSpecificExcep
tion(ErrorCodeConverter.java:90)
at net.sf.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConver
ter.java:79)
at net.sf.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionH
elper.java:30)
at net.sf.hibernate.collection.AbstractCollectionPersister.convert(Abstr
actCollectionPersister.java:728)
at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(Ab
stractCollectionPersister.java:291)
at net.sf.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.ja
va:3303)
at net.sf.hibernate.collection.PersistentCollection.forceInitialization(
PersistentCollection.java:336)
at net.sf.hibernate.Hibernate.initialize(Hibernate.java:256)
at com.negrid.onlinetest.db.manager.NeGridTestManager.getReviews(NeGridT
estManager.java:343)
at com.negrid.onlinetest.struts.action.TestReviewAction.getReviews(TestR
eviewAction.java:105)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchActio
n.java:280)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:
216)
at org.apache.struts.action.RequestProcessor.processActionPerform(Reques
tProcessor.java:484)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.ja
va:274)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:148
2)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:173)
at com.negrid.onlinetest.struts.filters.SetCharacterEncodingFilter.doFil
ter(SetCharacterEncodingFilter.java:97)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:173)
at com.negrid.onlinetest.struts.filters.SetCharacterEncodingFilter.doFil
ter(SetCharacterEncodingFilter.java:97)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValv
eContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(Standard
ContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValv
eContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValv
eContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValv
eContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValv
eContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)

at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:16
0)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java
:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.proce
ssConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java
:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadP
ool.java:684)
at java.lang.Thread.run(Thread.java:534)
Caused by: java.sql.SQLException: ORA-00911: invalid character

at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java
:125)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:305)
at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:272)
at oracle.jdbc.driver.T4C8Oall.receive(T4C8Oall.java:623)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.
java:181)
at oracle.jdbc.driver.T4CPreparedStatement.execute_for_describe(T4CPrepa
redStatement.java:420)
at oracle.jdbc.driver.OracleStatement.execute_maybe_describe(OracleState
ment.java:896)
at oracle.jdbc.driver.T4CPreparedStatement.execute_maybe_describe(T4CPre
paredStatement.java:452)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStateme
nt.java:986)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePrep
aredStatement.java:2888)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePrepare
dStatement.java:2929)
at net.sf.hibernate.impl.BatcherImpl.getResultSet(BatcherImpl.java:88)
at net.sf.hibernate.loader.Loader.getResultSet(Loader.java:875)
at net.sf.hibernate.loader.Loader.doQuery(Loader.java:269)
at net.sf.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections
(Loader.java:133)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:990)
at net.sf.hibernate.loader.Loader.loadCollection(Loader.java:965)
at net.sf.hibernate.loader.OneToManyLoader.initialize(OneToManyLoader.ja
va:93)
at net.sf.hibernate.collection.AbstractCollectionPersister.initialize(Ab
stractCollectionPersister.java:288)
... 47 more

Name and version of the database you are using:

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

I hope anybody can help me conquer it.Thank you.
Best Regards!

I also use struts as the framework of the project
Next are some of the classes I use
NeGridTestManager.java (class that wrap the hibernate properties and provides interfaces for users to manipulate database)
/*
* retrieve review records according to the T_ID foreign key
* @param testRecord
*/
public static Review[] getReviews(TestRecord testRecord){
Session session=null;
Transaction tx=null;
Set reviews=null;
try{
session=HibernateSessionFactory.currentSession(); //create hibernate session
tx=session.beginTransaction();//begin transaction
/*
testRecord=(TestRecord)session.load(TestRecord.class,id);
if(!Hibernate.isInitialized(testRecord.getReviews()))
Hibernate.initialize(testRecord.getReviews());
*/
session.lock(testRecord,LockMode.READ);
if(!Hibernate.isInitialized(testRecord.getReviews()))
Hibernate.initialize(testRecord.getReviews());
reviews=testRecord.getReviews();
tx.commit();
session.close();
} catch(HibernateException e){
e.printStackTrace();
//if an error occurs,better to rollback transaction
try{
if(tx!=null)
tx.rollback();
}catch(HibernateException e1){
e1.printStackTrace();
}
}finally{
try{
if(session!=null)
session.close();
}catch(HibernateException e2){
e2.printStackTrace();
}
}
return (Review[]) reviews.toArray(new Review[0]);
}
TestReviewAction.java(the action class )
public class TestReviewAction extends DispatchAction{
/**
* Method execute
* @param mapping
* @param form
* @param request
* @param response
* @return ActionForward
*/
public ActionForward getReviews(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
TestReviewForm testReviewForm=(TestReviewForm)form;
HttpSession session=request.getSession();
testReviewForm=(TestReviewForm)session.getAttribute("testReviewForm");
int index=Integer.valueOf(request.getParameter("index")).intValue();
TestRecord[] testRecords=testReviewForm.getTestRecords();
TestRecord testRecord=testRecords[index];
request.setAttribute("reviews",NeGridTestManager.getReviews(testRecord));
return mapping.findForward("showReviews");
}
}
/**
* Method execute
* @param mapping
* @param form
* @param request
* @param response
* @return ActionForward
*/
public ActionForward getTestRecords(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) {
TestReviewForm testReviewForm;
if(form==null)
testReviewForm=new TestReviewForm();
else
testReviewForm=(TestReviewForm)form;
long studentId=testReviewForm.getStudentId().longValue();//it receives a request parameter from a jsp form submit
TestRecord[] testRecords=NeGridTestManager.getTestRecordsByStudentId(studentId);
testReviewForm.setTestRecords(testRecords);
request.setAttribute("id",testReviewForm.getStudentId());
return mapping.findForward("showTestRecords");
}