Hi Truong,
seems that the Apache server removed the attached files. Could you
please send the source code as normal text?
By the way the generated DB seems to be consistent, so the problem was
caused by OJB or "wrong usage" of OJB.
regards,
Armin
Truong Nguyen Huy wrote:
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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