Thank you very much for your attention to my problem.
I am sorry not supply full detail for you to test the problem. Let me
put straight my issue.
Here is the script to create database (MySQL):
-------------------------------------------------------------------
# MySQL-Front 3.2 (Build 14.8)
/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES latin1 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='SYSTEM' */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE */;
/*!40101 SET
SQL_MODE='STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION'
*/;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES */;
/*!40103 SET SQL_NOTES='ON' */;
# Host: localhost Database: test
# ------------------------------------------------------
# Server version 5.0.41-community-nt
DROP DATABASE IF EXISTS `test`;
CREATE DATABASE `test` /*!40100 DEFAULT CHARACTER SET latin1 */;
USE `test`;
#
# Table structure for table car
#
CREATE TABLE `car` (
`id` int(10) unsigned NOT NULL auto_increment,
`licencenum` varchar(45) NOT NULL,
`personid` int(10) unsigned NOT NULL,
PRIMARY KEY (`id`),
KEY `FK_car_1` (`personid`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
#
# Dumping data for table car
#
INSERT INTO `car` VALUES (1,'52S4-1800',1);
INSERT INTO `car` VALUES (2,'52S4-9448',1);
INSERT INTO `car` VALUES (3,'50L1-2381',2);
#
# Table structure for table person
#
CREATE TABLE `person` (
`id` int(10) unsigned NOT NULL auto_increment,
`name` varchar(45) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
#
# Dumping data for table person
#
INSERT INTO `person` VALUES (1,'Truong');
INSERT INTO `person` VALUES (2,'Tuan');
INSERT INTO `person` VALUES (3,'Nguyen');
INSERT INTO `person` VALUES (4,'Tam');
#
# Table structure for table project
#
CREATE TABLE `project` (
`id` int(10) unsigned NOT NULL auto_increment,
`Name` varchar(45) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
#
# Dumping data for table project
#
INSERT INTO `project` VALUES (1,'EdenTree');
INSERT INTO `project` VALUES (2,'Simpatica');
#
# Table structure for table project_person
#
CREATE TABLE `project_person` (
`project_id` int(10) unsigned NOT NULL default '0',
`person_id` int(10) unsigned NOT NULL default '0',
PRIMARY KEY (`project_id`,`person_id`),
KEY `FK_project_person_1` (`person_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
#
# Dumping data for table project_person
#
INSERT INTO `project_person` VALUES (1,1);
INSERT INTO `project_person` VALUES (1,3);
INSERT INTO `project_person` VALUES (2,1);
INSERT INTO `project_person` VALUES (2,2);
INSERT INTO `project_person` VALUES (2,3);
INSERT INTO `project_person` VALUES (2,4);
#
# Foreign keys for table car
#
ALTER TABLE `car`
ADD FOREIGN KEY (`personid`) REFERENCES `person` (`id`);
#
# Foreign keys for table project_person
#
ALTER TABLE `project_person`
ADD FOREIGN KEY (`person_id`) REFERENCES `person` (`id`),
ADD FOREIGN KEY (`project_id`) REFERENCES `project` (`id`);
/*!40111 SET [EMAIL PROTECTED] */;
/*!40101 SET [EMAIL PROTECTED] */;
/*!40103 SET [EMAIL PROTECTED] */;
/*!40101 SET [EMAIL PROTECTED] */;
/*!40101 SET [EMAIL PROTECTED] */;
/*!40101 SET [EMAIL PROTECTED] */;
I have attached the source code. Please find it in the attachment.
--------------------------------------------------------------------------------------------
Here is the list of library I use:
--------------------------------------------
commons-collections-3.1.jar
commons-dbcp-1.2.1.jar
commons-lang-2.1.jar
commons-pool-1.2.jar
commons-transaction-1.1.jar
commons-logging-1.0.4.jar
db-ojb-1.0.4.jar
mysql-connector-java-5.0.7-bin.jar
log4j-1.2.8.jar
OJB version that I use: 1.0.4. I download from a mirror location of Apache
OJB
------------------------------------------------------------------------
Thanks for your help,
Regards,
Truong Nguyen
On 9/7/07, Armin Waibel <[EMAIL PROTECTED] > wrote:
>
> Hi,
>
> your mapping seems ok. Sounds like a bug in OJB.
> I tried to reproduce your problem without success (using latest version
> of OJB from SVN OJB_1_0_RELEASE branch) - never get a NPE.
> I use the mapping from the m:n example (with Person and Project) and do:
>
> oid = broker.serviceIdentity().buildIdentity(Person.class, new
> Integer(1));
> person = (Person) broker.getObjectByIdentity(oid);
>
> No NPE. How can I reproduce your problem?
>
> regards,
> Armin
>
>
> Truong Nguyen Huy wrote:
> > Hi all,
> >
> > I have a problem when using m:n mapping. I will describe it below.
> >
> > I just implement a tutorial in this link
> > http://db.apache.org/ojb/docu/guides/basic-technique.html#Support+for+Non-Decomposed+m%3An+Mappings
>
> >
> >
> > There are three table: PERSON, PROJECT, PROJECT_PERSON.
> > PROJECT_PERSON is the connector standing for m:n relation between
> > PROJECT and PERSON.
> >
> > PROJECT(id,name) PERSON(id,name) PROJECT_PERSON(project_id,
> > person_id)
> >
> > The mapping file as below:____________________________
> >
> > <!-- vn.com.tma.testOJB.Person -->
> > <class-descriptor class="vn.com.tma.testOJB.Person "
> >
> >
> > table="person" <field-descriptor name="id" column="id"
> > jdbc-type="INTEGER" primarykey="true" autoincrement="true" />
> > <field-descriptor name="name" column="name" jdbc-type="VARCHAR" />
> >
> >
> > <collection-descriptor name="projects" collection-class="
> > org.apache.ojb.broker.util.collections.ManageableArrayList "
> > element-class-ref="vn.com.tma.testOJB.Project" auto-retrieve="true"
> > auto-update="true" indirection-table="PROJECT_PERSON"
> >>
> > <fk-pointing-to-this-class column="PERSON_ID"/>
> > <fk-pointing-to-element-class column="PROJECT_ID"/>
> > </collection-descriptor>
> >
> > </class-descriptor>
> >
> > <!-- vn.com.tma.testOJB.Project -->
> > <class-descriptor class="vn.com.tma.testOJB.Project"
> >
> > table="project" <field-descriptor name="id" column="id"
> > jdbc-type="INTEGER" primarykey="true" autoincrement="true" />
> > <field-descriptor name="name" column="Name" jdbc-type="VARCHAR" />
> > <collection-descriptor name="employees" collection-class="
> > org.apache.ojb.broker.util.collections.ManageableArrayList "
> > element-class-ref="vn.com.tma.testOJB.Person" auto-retrieve="true"
> > auto-update="false" indirection-table="PROJECT_PERSON"
> >>
> > <fk-pointing-to-this-class column="PROJECT_ID"/>
> > <fk-pointing-to-element-class column="PERSON_ID"/>
> > </collection-descriptor> </class-descriptor>
> >
> > When I run these codes, it has error: PersistenceBroker broker =
> > PersistenceBrokerFactory.defaultPersistenceBroker(); Identity oid =
> > broker.serviceIdentity().buildIdentity(Person.class, new Integer(1));
> > Person person = (Person) broker.getObjectByIdentity(oid);
> >
> > The error is caused by the third line. This is the exception stack:
> >
> > Exception in thread "main"
> > org.apache.ojb.broker.PersistenceBrokerException:
> > java.lang.NullPointerException at
> > org.apache.ojb.broker.core.QueryReferenceBroker.getCollectionByQuery
> (Unknown
> > Source) at
> > org.apache.ojb.broker.core.QueryReferenceBroker.doRetrieveCollection
> (Unknown
> > Source) at
> > org.apache.ojb.broker.core.QueryReferenceBroker.retrieveCollection
> (Unknown
> > Source) at
> > org.apache.ojb.broker.core.QueryReferenceBroker.doRetrieveCollections
> (Unknown
> > Source) at
> > org.apache.ojb.broker.core.QueryReferenceBroker.retrieveCollections(Unknown
> > Source) at
> > org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Unknown
> > Source) at
> > org.apache.ojb.broker.core.PersistenceBrokerImpl.doGetObjectByIdentity
> (Unknown
> > Source) at
> > org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByIdentity
> (Unknown
> > Source) at
> >
> org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByIdentity
> (Unknown
> > Source) at
> >
> org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByIdentity
> (Unknown
> > Source) at vn.com.tma.main.Run.main(Run.java:41) Caused by:
> > java.lang.NullPointerException at
> >
> org.apache.ojb.broker.accesslayer.MtoNCollectionPrefetcher.associateBatched(Unknown
> > Source) at
> >
> org.apache.ojb.broker.accesslayer.MtoNCollectionPrefetcher.prefetchRelationship
> (Unknown
> > Source) at
> > org.apache.ojb.broker.core.QueryReferenceBroker.performRetrievalTasks(Unknown
> > Source) at
> > org.apache.ojb.broker.core.QueryReferenceBroker.getCollectionByQuery
> (Unknown
> > Source) ... 11 more
> >
> > But if I change auto-archive to "false" in arbitrary one of two
> > class-descriptor, there is no error anymore. But it still causes the
> > same error when I use method "broker.retrieveAllReferences()" on an
> > instance of the rest class-descriptor.
> >
> > Only when I change auto-archive of both class-descriptor to "false",
> > the error is omitted.
> >
> > Can anyone explain why and help me resolve the problem when using
> > auto-archive="true" on both class-descriptor? Thank you very for your
> > help.
> >
>
>
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>
--
Regards,
Truong Nguyen Huy
--
Regards,
Truong Nguyen Huy
