I've found the 'source' of the problem. In short it is about instantiating a collection of inverse foreign-keys, i.e. references to objects. When I change my repository.xml and omit the collection descriptors it works! (yay). Otherwise this is what is happening: get Article -> get Article-Type -> create collection of inverse foreign keys -> (does intermediate query, fetching all articles with same article-type), at end of iterating this collection it goes bewm.
Hopefully this is of any help in order to tackle the / by zero error. Let me know if you need more information.
Regards, Mike Ahlers
Brian McCallister wrote:
Which version of OJB are you using? Line numbers don't match up to the one I have, which is, admittedly, cvs head -- though rc6 and cvs head are pretty similar right now.
Okay, some try-the-common-things-first:
Try changing the PK and FK values to Integer types instead of int. Using the primitives can really boggle OJB as it is not safe to presume 0 is equivalent to not-set (null).
Test.
Remove the "default-fetch" as it only applies to JDO rinse, repeat.
Will look at more carefully asap =)
-Brian
On Apr 7, 2004, at 9:56 AM, Mike Ahlers wrote:
Hi Brian,
I can try... let me describe what I got so far. After digging deeper into this and producing some relevant debug statements I find the following written on my console:
console output:
--- start snippet ---
NVTPDataAccessObject2: getArticle: called with id: 56
[org.apache.ojb.broker.accesslayer.JdbcAccessImpl] DEBUG: executeQuery : Query from class nl.hippo.nvpt.Articles where [id = 56]
[org.apache.ojb.broker.accesslayer.sql.SqlGeneratorDefaultImpl] DEBUG: SQL:SELECT A0.TELEFOON,A0.TREFWOORDEN,A0.TYPE,A0.PARTNER,A0.PASSWORD,A0.KLANT,A0.L OGIN,A0
.WERKZAAMBIJ,A0.TITEL,A0.OMSCHRIJVING,A0.MATRICE_ID,A0.EMAIL,A0.CONTACT PERSOON,A0.BESTAND,A0.CORP_ID,A0.BRON,A0.ID FROM ARTICLES A0 WHERE A0.ID = ?
[org.apache.ojb.broker.accesslayer.JdbcAccessImpl] DEBUG: executeQuery: [EMAIL PROTECTED]: SELECT A0.TELEFOON,A0.TREFWOORDEN,A0.TYPE,A0.PARTNER,A0.PASSWORD,A0.KLANT,A0.L OGIN,A0.WERKZAAMBIJ,A0.TITEL,A0.OMSCHRIJVING,A0.
MATRICE_ID,A0.EMAIL,A0.CONTACTPERSOON,A0.BESTAND,A0.CORP_ID,A0.BRON,A0. ID FROM ARTICLES A0 WHERE A0.ID = 56
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: RsIterator[org.apache.ojb.broker.accesslayer.RsQueryObject[query: Query from class nl.hippo.nvpt.Articles where [id = 56], class descriptor: nl.hippo.nvpt.Articles]] initialized
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
[org.apache.ojb.broker.accesslayer.sql.SqlGeneratorDefaultImpl] DEBUG: SQL:SELECT NAAM,OMSCHRIJVING,ID FROM ARTICLE_TYPES WHERE ID = ?
[org.apache.ojb.broker.accesslayer.JdbcAccessImpl] DEBUG: executeQuery : Query from class nl.hippo.nvpt.Articles where [type = 3]
^^^^^^
[org.apache.ojb.broker.accesslayer.sql.SqlGeneratorDefaultImpl] DEBUG: SQL:SELECT A0.TELEFOON,A0.TREFWOORDEN,A0.TYPE,A0.PARTNER,A0.PASSWORD,A0.KLANT,A0.L OGIN,A0
.WERKZAAMBIJ,A0.TITEL,A0.OMSCHRIJVING,A0.MATRICE_ID,A0.EMAIL,A0.CONTACT PERSOON,A0.BESTAND,A0.CORP_ID,A0.BRON,A0.ID FROM ARTICLES A0 WHERE A0.TYPE = ?
[org.apache.ojb.broker.accesslayer.JdbcAccessImpl] DEBUG: executeQuery: [EMAIL PROTECTED]: SELECT A0.TELEFOON,A0.TREFWOORDEN,A0.TYPE,A0.PARTNER,A0.PASSWORD,A0.KLANT,A0.L OGIN,A0.WERKZAAMBIJ,A0.TITEL,A0.OMSCHRIJVING,A0.
MATRICE_ID,A0.EMAIL,A0.CONTACTPERSOON,A0.BESTAND,A0.CORP_ID,A0.BRON,A0. ID FROM ARTICLES A0 WHERE A0.TYPE = 3
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: RsIterator[org.apache.ojb.
broker.accesslayer.RsQueryObject[query: Query from class nl.hippo.nvpt.Articles where [type = 3], class descriptor: nl.hippo.nvpt.Articles]] initialized
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
...
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> true
[org.apache.ojb.broker.accesslayer.RsIterator] DEBUG: hasNext() -> false
java.lang.ArithmeticException: / by zero
at org.apache.ojb.broker.accesslayer.BasePrefetcher.<init>(BasePrefetcher. java:115)
at org.apache.ojb.broker.accesslayer.RelationshipPrefetcherImpl.<init>(Rel ationshipPrefetcherImpl.java:78)
at org.apache.ojb.broker.accesslayer.CollectionPrefetcher.<init>(Collectio nPrefetcher.java:97)
at org.apache.ojb.broker.accesslayer.RelationshipPrefetcherFactory.createR elationshipPrefetcher(RelationshipPrefetcherFactory.java:85)
at org.apache.ojb.broker.core.QueryReferenceBroker.performRetrievalTasks(Q ueryReferenceBroker.java:315)
at org.apache.ojb.broker.core.QueryReferenceBroker.getCollectionByQuery(Qu eryReferenceBroker.java:185)
at org.apache.ojb.broker.core.QueryReferenceBroker.getCollectionByQuery(Qu eryReferenceBroker.java:242)
at org.apache.ojb.broker.core.QueryReferenceBroker.getCollectionByQuery(Qu eryReferenceBroker.java:262)
at org.apache.ojb.broker.core.QueryReferenceBroker.retrieveCollection(Quer yReferenceBroker.java:513)
at org.apache.ojb.broker.core.QueryReferenceBroker.retrieveCollections(Que ryReferenceBroker.java:695)
at org.apache.ojb.broker.core.PersistenceBrokerImpl.getDBObject(Persistenc eBrokerImpl.java:1153)
at org.apache.ojb.broker.core.PersistenceBrokerImpl.doGetObjectByIdentity( PersistenceBrokerImpl.java:1217)
at org.apache.ojb.broker.core.QueryReferenceBroker.getReferencedObject(Que ryReferenceBroker.java:478)
at org.apache.ojb.broker.core.QueryReferenceBroker.retrieveReference(Query ReferenceBroker.java:358)
at org.apache.ojb.broker.core.QueryReferenceBroker.retrieveReferences(Quer yReferenceBroker.java:400)
at org.apache.ojb.broker.accesslayer.RsIterator.getObjectFromResultSet(RsI terator.java:501)
at org.apache.ojb.broker.accesslayer.RsIterator.next(RsIterator.java:293)
at org.apache.ojb.broker.core.PersistenceBrokerImpl.getObjectByQuery(Persi stenceBrokerImpl.java:1298)
at org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByQuery (DelegatingPersistenceBroker.java:291)
at org.apache.ojb.broker.core.DelegatingPersistenceBroker.getObjectByQuery (DelegatingPersistenceBroker.java:291)
at nl.hippo.nvpt.NVTPDataAccessObject2.getArticle(Unknown Source)
--- end snippet ---
Note the sudden 'translation' of 'Article_types' into 'Articles'. I am expecting a query like: Query from class nl.hippo.nvpt.Article_types where [type = 3] and not Query from class nl.hippo.nvpt.Articles where [type = 3]. Could this a bug in the SqlGeneratorDefaultImpl regarding nested queries? Anyways, this is what I am trying to map:
repository.xml:
--- start snippet ---
<class-descriptor class="nl.hippo.nvpt.Articles" table="ARTICLES">
<field-descriptor name="id" primarykey="true" default-fetch="true" column="ID" jdbc-type="INTEGER"/>
<field-descriptor name="type" default-fetch="true" column="TYPE" jdbc-type="INTEGER"/>
....
<reference-descriptor name="article_types" class-ref="nl.hippo.nvpt.Article_types" auto-update="false" auto-delete="false">
<foreignkey field-ref="type"/>
</reference-descriptor>
</class-descriptor>
--- end snippet ---
The following classes are generated (like the repository.xml) by Druid and has setters and getters.
Articles.java: --- start snippet --- public class Articles { public int id; public int type; public Article_types article_types; ... } --- end snippet ---
Article_types: --- start snippet --- public class Article_types { public int id; public String naam; public String omschrijving; } --- end snippet ---
My data access object looks like this:
--- start snippet ---
public Articles getArticle(int id) {
...
System.out.println("NVTPDataAccessObject2: getArticle: called with id: " + id);
broker = PersistenceBrokerFactory.defaultPersistenceBroker();
// Create criteria
criteria = new Criteria();
criteria.addEqualTo("id", new Integer(id)); // Refine criteria
// Create query
query = new QueryByCriteria(Articles.class, criteria);
result = (Articles) broker.getObjectByQuery(query);
...
return result;
--- end snippet ---
Brian McCallister wrote:
Any chance you can post the relevent repository_user.xml snippets and an outline at least of what they map to? More than happy to help you work out what's going on =)
I have never seen divide by zero errors from OJB =(
Also, do you get the same problem if you try the query via the PersistenceBroker api instead of the JDO api?
-Brian
On Apr 7, 2004, at 5:44 AM, Mike Ahlers wrote:
Hi,
I am a new kid on the block and work with the OJB/JDO block. Using a database with no relations works perfectly, however when I increase complexity and use foreign keys I fail to get it working. The following error is what I get:
[org.apache.ojb.broker.accesslayer.RsIterator] ERROR: Error while iterate Result Set for query org.apache.ojb.broker.accesslayer.RsQueryObject[query: Query from class nl.hippo.nvpt.Articles where [id = 55], class descriptor: nl.hippo.nvpt.Ar
ticles]
/ by zero java.lang.ArithmeticException: / by zero
Can anybody explain why iterating over a result-set gives a div by zero?
Thanks in advance, Mike Ahlers
