objectbridge-developers — public list for developer issues

RE: [OJB-developers] ERROR: Server configuration denies access to data source

[Alex C. <ac...@in...>]

From: Ricardo Arg=FCello [mailto:ri...@ya...]

> It turns out that this error:
>   java.sql.SQLException: Server configuration denies access=20
> to data source
>=20
> was caused because MySql used its "max_connections" limit of 100.
>=20
> I tried to initialize MySql with a parameter of=20
> max_connections=3D1000, but it gave me the same error.

Are you sure?  I usually see this error when there's a permissions =
problem.

-0xe1a

Re: [OJB-developers] ERROR: Server configuration denies access to data source

[<ri...@ya...>]

Hello,

It turns out that this error:
  java.sql.SQLException: Server configuration denies access to data =
source

was caused because MySql used its "max_connections" limit of 100.

I tried to initialize MySql with a parameter of max_connections=3D1000, =
but it gave me the same error.

What leads me to think that it's a problem with OJB not closing =
connections.

It looks like OJB open a lot of connections trying to materialize the =
dynamic proxies, but then it stops and gives the Exception, because all =
the connections are occupied.

Why does OJB open so many connections when using dynamic proxies?

Thanks in advance,

Ricardo Arguello


----- Original Message -----=20
From: "Mahler Thomas" <tho...@it...>
To: "'Ricardo Arg=FCello'" <ri...@ya...>
Cc: "Objectbridge (E-Mail)" =
<obj...@li...>
Sent: Tuesday, February 19, 2002 4:48 AM
Subject: AW: [OJB-developers] ERROR: Server configuration denies access =
to data source


> Hi Ricardo,
>=20
> >=20
> > Hello,
> >=20
> > Since OJB is performing REALLY slowly, I tried to add the=20
> > next tag to my repository.xml file:
> >=20
> >   <class.proxy>dynamic</class.proxy>
> >=20
> > in every <ClassDescriptor> tag.
> >=20
> > All my objects implement an interface, so this theorically=20
> > should work fine.
> > That's the only thing I changed in this file, and now I'm=20
> > getting this strange exception:
> =20
> > [DEFAULT] ERROR: Server configuration denies access to data source
> > java.sql.SQLException: Server configuration denies access to=20
> > data source
> >         at org.gjt.mm.mysql.MysqlIO.init(Unknown Source)
> >         at org.gjt.mm.mysql.Connection.connectionInit(Unknown =
Source)
> >         at=20
> > org.gjt.mm.mysql.jdbc2.Connection.connectionInit(Unknown Source)
> >         at org.gjt.mm.mysql.Driver.connect(Unknown Source)
> >         at=20
> > java.sql.DriverManager.getConnection(DriverManager.java:517)
> >         at=20
> > java.sql.DriverManager.getConnection(DriverManager.java:177)
> >         at=20
> > =
ojb.broker.accesslayer.ConnectionFactoryDefaultImpl.newConnection(Con
> > nectionFactoryDefaultImpl.java:72)
> <snip>
>=20
> OK this exception is raised during the materilization of a proxy. But =
the
> error is NOT Proxy related at all. You get an Error from the the MySQL
> driver.
> I'm not a MySQL expert thus I can't help here.
>=20
> >=20
> >=20
> > --------------------------------------------------------------
> > ------------
> >=20
> > After a LOT of these messages: =20
> >=20
> > [DEFAULT] WARN: problems with platform=20
> > ojb.broker.platforms.PlatformMySQLImpl:
> > ojb.broker.platforms.PlatformMySQLImpl
> > [DEFAULT] WARN: OJB will use PlatformDefaultImpl instead
> >=20
>=20
> This is totally harmless. It just tells you that OJB does not use any =
MySql
> specific PlatForm code.
>=20
> >=20
> >=20
> > Do you have any idea of what's might the problem be?
>=20
> IMHO this is a MySQL specific problem.
> =20
> > Besides this, how can I make OJB perform faster?
> >=20
>=20
> Mhh.
> Of course using an O/R layer has a certain impact on performance.
> If you are using handcoded JDBC and handcoded mappings you can do =
things
> much faster.
> There is nothing like a free lunch !
>=20
> But: has been carefully designed to minimize the performance impact.
> There is a special JUnit target 'performance'
>=20
> By calling 'build.sh performance' you can execute the OJB performance
> testsuite.
> The testsuite runs to tests:
> 1. running five tescenarios using OJB
> 2. running the same scenarios with manual coded JDBC calls.
>=20
> If you are executing it out of the box the tests are executed against =
the
> HSQLDB database that ships with OJB.
> You will see that the OJB mode is about half as fast as the native =
JDBC
> mode.
> (For instance inserting 10.000 Objects takes about 2500 msecs using =
JDBC and
> about 5000 msecs using OJB on one of my machines.)
>=20
> This sounds bad. But you have to take in account that HDSQL does =
everything
> in memory and that there is no network overhead involved.
>=20
> Now just change the target database (in the repository.xml) to say MS =
access
> and you will see a totally different picture:
> Inserting 10.000 object via JDBC takes 50.000 msecs and 52.500 msecs =
using
> OJB.
>=20
> You see: the absolute OJB overhead remains the same but the factor =
OJB/JDBC
> decreases enormously.
>=20
> Please try this performance test against your target database and tell =
us
> your exact results. I am almost sure that your results will look quite
> similar!
>=20
>=20
> On the other hand: There has been a lot of work on OJB internals in =
the last
> months and it may well be that these refactorings had a negative =
performance
> impact. This must be carefully checked!
> We will need another performance tuning code-walkthrough before we can
> release OJB 1.0.
>=20
> HTH,
>=20
> Thomas
>=20
> >=20
> > Thanks in advance!
> >=20
> > Ricardo Arguello
> >=20
> >=20
> > _______________________________________________
> > Objectbridge-developers mailing list
> > Obj...@li...
> > https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
> >=20
> 

[OJB-developers] Scott Ambler Design and OJB

[Jason v. Z. <jv...@ze...>]

Hi,

I'm about to dig into OJB and I was wondering if any (Thomas, possibly)
can draw a short comparison between the design patterns of Scott Ambler
and OJB.

-- 
jvz.

Jason van Zyl
jv...@ap...

http://tambora.zenplex.org

AW: [OJB-developers] OJB OQL

[Mahler T. <tho...@it...>]

Hi Jakob,
 thanks for the patch!

I'm also no ANTLR and OQL expert but I will check your patch and =
integrate
it into the distribution.

What about your CVS problems? Did you get things running?

cu,

Thomas

> -----Urspr=FCngliche Nachricht-----
> Von: Jakob Braeuchi [mailto:jbr...@ho...]
> Gesendet: Mittwoch, 20. Februar 2002 08:31
> An: Objectbridge Developers List (E-mail)
> Betreff: [OJB-developers] OJB OQL
>=20
>=20
> hi,
>=20
> this patch fixes problems with OQL nil and between.
>=20
> query.create("select persons from brj.ojb.Person where=20
> geburtsDatum =3D nil");
>=20
> here the grammer was going into the equalityExpr method and did not
> recognize "nil".
>=20
> query.create("select persons from brj.ojb.Person where test=20
> between $1 and
> $2 and name like $3");
> query.bind(new Integer(80));
> query.bind(new Integer(100));
> query.bind("%er");
>=20
> in this case the bind assumed that each criterion should have only =
one
> parameter
> and looked for three criteria in the above example.
>=20
> i have to admit i'm neither an antlr nor an oql expert !
>=20
> jakob
>=20

[OJB-developers] OJB OQL

[Jakob B. <jbr...@ho...>]

hi,

this patch fixes problems with OQL nil and between.

query.create("select persons from brj.ojb.Person where geburtsDatum = nil");

here the grammer was going into the equalityExpr method and did not
recognize "nil".

query.create("select persons from brj.ojb.Person where test between $1 and
$2 and name like $3");
query.bind(new Integer(80));
query.bind(new Integer(100));
query.bind("%er");

in this case the bind assumed that each criterion should have only one
parameter
and looked for three criteria in the above example.

i have to admit i'm neither an antlr nor an oql expert !

jakob

AW: [OJB-developers] new Repository

[Mahler T. <tho...@it...>]

Hi Bertrand,

> 
> Hi Thomas
> 
> I saw in the contrib archive that there is a new repository dtd, ...
> Are they any plan to make it the default impl in the future?
> 

There have been a lot of discussions regarding the repository grammar.
Several people have worked on proposals for a better DTD (or schema).

I placed the latest snapshot of these efforts into the contrib archive to
allow others to play around with it.

A redesign of the repository grammar is one of the last open feature
requests for OJB 1.0.
There will definitely be a redesign to the DTD but I don't know yet how it
will look like exactly.
AFAIK no one is currently working on this issue.

Of course we will provide an XSL stylesheet that will help users to migrate
their 'old' OJB repositories to the new grammar.

Thomas

> Best Regards
> 
> Bertrand
> 
> 
> 
> _______________________________________________
> Objectbridge-developers mailing list
> Obj...@li...
> https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
> 

[OJB-developers] OJB reviewed ! [not to say re-invented ;-)]

[Mahler T. <tho...@it...>]

Hi all,
 
OJB has finally hit the academic world!
I found an interesting link on the web pointing to a BA thesis covering the
design of an O/R framework.
The Framework is called Jakamar.
http://www.lap.ttu.ee/erki/failid/konspekt/bakalaureusetoo/thesis.pdf
<http://www.lap.ttu.ee/erki/failid/konspekt/bakalaureusetoo/thesis.pdf> 
 
IMHO Jakamar reuses a lot of things from OJB and its underlying concepts.
The presentation gives a good overview of the Jakamar (OJB) architecture and
the design pattern based approach.
 
The thesis even contains a performance comparison between Jakamar and OJB
and a feature comparison. (I won't comment on those comparisons here)
 
I like some of the ideas presented (e.g. PersistenceBroker provides factory
methods to obtain queries). Sometimes the naming of classes is better than
in OJB.
 
I think it is a good idea to have a deeper look at this thesis. Maybe we can
ask the author to share ideas or even collaborate directly.
 
cu,
 
Thomas

AW: [OJB-developers] ERROR: Server configuration denies access to data source

[Mahler T. <tho...@it...>]

Hi Ricardo,

> 
> Hello,
> 
> Since OJB is performing REALLY slowly, I tried to add the 
> next tag to my repository.xml file:
> 
>   <class.proxy>dynamic</class.proxy>
> 
> in every <ClassDescriptor> tag.
> 
> All my objects implement an interface, so this theorically 
> should work fine.
> That's the only thing I changed in this file, and now I'm 
> getting this strange exception:
 
> [DEFAULT] ERROR: Server configuration denies access to data source
> java.sql.SQLException: Server configuration denies access to 
> data source
>         at org.gjt.mm.mysql.MysqlIO.init(Unknown Source)
>         at org.gjt.mm.mysql.Connection.connectionInit(Unknown Source)
>         at 
> org.gjt.mm.mysql.jdbc2.Connection.connectionInit(Unknown Source)
>         at org.gjt.mm.mysql.Driver.connect(Unknown Source)
>         at 
> java.sql.DriverManager.getConnection(DriverManager.java:517)
>         at 
> java.sql.DriverManager.getConnection(DriverManager.java:177)
>         at 
> ojb.broker.accesslayer.ConnectionFactoryDefaultImpl.newConnection(Con
> nectionFactoryDefaultImpl.java:72)
<snip>

OK this exception is raised during the materilization of a proxy. But the
error is NOT Proxy related at all. You get an Error from the the MySQL
driver.
I'm not a MySQL expert thus I can't help here.

> 
> 
> --------------------------------------------------------------
> ------------
> 
> After a LOT of these messages:  
> 
> [DEFAULT] WARN: problems with platform 
> ojb.broker.platforms.PlatformMySQLImpl:
> ojb.broker.platforms.PlatformMySQLImpl
> [DEFAULT] WARN: OJB will use PlatformDefaultImpl instead
> 

This is totally harmless. It just tells you that OJB does not use any MySql
specific PlatForm code.

> 
> 
> Do you have any idea of what's might the problem be?

IMHO this is a MySQL specific problem.
 
> Besides this, how can I make OJB perform faster?
> 

Mhh.
Of course using an O/R layer has a certain impact on performance.
If you are using handcoded JDBC and handcoded mappings you can do things
much faster.
There is nothing like a free lunch !

But: has been carefully designed to minimize the performance impact.
There is a special JUnit target 'performance'

By calling 'build.sh performance' you can execute the OJB performance
testsuite.
The testsuite runs to tests:
1. running five tescenarios using OJB
2. running the same scenarios with manual coded JDBC calls.

If you are executing it out of the box the tests are executed against the
HSQLDB database that ships with OJB.
You will see that the OJB mode is about half as fast as the native JDBC
mode.
(For instance inserting 10.000 Objects takes about 2500 msecs using JDBC and
about 5000 msecs using OJB on one of my machines.)

This sounds bad. But you have to take in account that HDSQL does everything
in memory and that there is no network overhead involved.

Now just change the target database (in the repository.xml) to say MS access
and you will see a totally different picture:
Inserting 10.000 object via JDBC takes 50.000 msecs and 52.500 msecs using
OJB.

You see: the absolute OJB overhead remains the same but the factor OJB/JDBC
decreases enormously.

Please try this performance test against your target database and tell us
your exact results. I am almost sure that your results will look quite
similar!


On the other hand: There has been a lot of work on OJB internals in the last
months and it may well be that these refactorings had a negative performance
impact. This must be carefully checked!
We will need another performance tuning code-walkthrough before we can
release OJB 1.0.

HTH,

Thomas

> 
> Thanks in advance!
> 
> Ricardo Arguello
> 
> 
> _______________________________________________
> Objectbridge-developers mailing list
> Obj...@li...
> https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
> 

[OJB-developers] new Repository

[<ber...@wa...>]

Hi Thomas

I saw in the contrib archive that there is a new repository dtd, ...
Are they any plan to make it the default impl in the future?

Best Regards

Bertrand

[OJB-developers] RowReader

[<ber...@wa...>]

Hi,

It seems that the RowReaderDefaultImpl class has change. I just post this
mail help person if they have the same problem.

ReadObjectFrom use an Object array as his first argument and not a rs
anymore.
It was a bit misleading because Thomas hasn't had the time to update the
documentation yet. The Javadoc has the right method signature but the
docstring still refer to the rs.
Tutorial need to be updated too.

Looking at the test class it is easy to find the solution. Change your
RowReader ReadObjectFrom to also use a object array and call
super.ReadObjectFrom with the row.

Best regards

Bertrand

[OJB-developers] ERROR: Server configuration denies access to data source

[<ri...@ya...>]

Hello,

Since OJB is performing REALLY slowly, I tried to add the next tag to my =
repository.xml file:

  <class.proxy>dynamic</class.proxy>

in every <ClassDescriptor> tag.

All my objects implement an interface, so this theorically should work =
fine.
That's the only thing I changed in this file, and now I'm getting this =
strange exception:

[DEFAULT] ERROR: Server configuration denies access to data source
java.sql.SQLException: Server configuration denies access to data source
        at org.gjt.mm.mysql.MysqlIO.init(Unknown Source)
        at org.gjt.mm.mysql.Connection.connectionInit(Unknown Source)
        at org.gjt.mm.mysql.jdbc2.Connection.connectionInit(Unknown =
Source)
        at org.gjt.mm.mysql.Driver.connect(Unknown Source)
        at java.sql.DriverManager.getConnection(DriverManager.java:517)
        at java.sql.DriverManager.getConnection(DriverManager.java:177)
        at =
ojb.broker.accesslayer.ConnectionFactoryDefaultImpl.newConnection(Con
nectionFactoryDefaultImpl.java:72)
        at =
ojb.broker.accesslayer.ConnectionManager.getNewConnection(ConnectionM
anager.java:106)
        at =
ojb.broker.accesslayer.ConnectionManager.getConnectionForClassDescrip
tor(ConnectionManager.java:93)
        at =
ojb.broker.accesslayer.StatementsForClass.getConnection(StatementsFor
Class.java:134)
        at =
ojb.broker.accesslayer.StatementsForClass.prepareStatement(Statements
ForClass.java:152)
        at =
ojb.broker.accesslayer.StatementsForClass.getSelectByPKStmt(Statement
sForClass.java:370)
        at =
ojb.broker.accesslayer.StatementManager.getSelectByPKStatement(Statem
entManager.java:439)
        at =
ojb.broker.accesslayer.JdbcAccess.materializeObject(JdbcAccess.java:3
39)
        at =
ojb.broker.singlevm.PersistenceBrokerImpl.getDBObject(PersistenceBrok
erImpl.java:1090)
        at =
ojb.broker.singlevm.PersistenceBrokerImpl.getObjectByIdentity(Persist
enceBrokerImpl.java:1208)
        at =
ojb.broker.accesslayer.IndirectionHandler.materializeSubject(Indirect
ionHandler.java:206)
        at =
ojb.broker.accesslayer.IndirectionHandler.getRealSubject(IndirectionH
andler.java:193)
        at =
ojb.broker.accesslayer.IndirectionHandler.invoke(IndirectionHandler.j
ava:163)
        at $Proxy0.getNombre(Unknown Source)
        at =
charlie.util.JavascriptHelper.generateProyectosOptions(JavascriptHelp
er.java)
        at org.apache.jsp.tarea$jsp._jspService(tarea$jsp.java:144)
        at =
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at =
org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspSer
vlet.java:202)
        at =
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:3
82)
        at =
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:474)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at =
org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDisp
atcher.java:679)
        at =
org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationD
ispatcher.java:431)
        at =
org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDis
patcher.java:355)
        at =
org.apache.struts.action.ActionServlet.processValidate(ActionServlet.
java:2149)
        at =
org.apache.struts.action.ActionServlet.process(ActionServlet.java:156
5)
        at =
org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:492)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at =
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:247)
        at =
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:193)
        at =
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:243)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:566)
        at =
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:472)
        at =
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

        at =
org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:201)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:566)
        at =
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:472)
        at =
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

        at =
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:
2344)
        at =
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:164)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:566)
        at =
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatche
rValve.java:170)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:564)
        at =
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:170)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:564)
        at =
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:
462)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:564)
        at =
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:472)
        at =
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

        at =
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:163)
        at =
org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline
.java:566)
        at =
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.jav
a:472)
        at =
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:943)

        at =
org.apache.catalina.connector.http.HttpProcessor.process(HttpProcesso
r.java:1011)
        at =
org.apache.catalina.connector.http.HttpProcessor.run(HttpProcessor.ja
va:1106)
        at java.lang.Thread.run(Thread.java:484)


-------------------------------------------------------------------------=
-

After a LOT of these messages: =20

[DEFAULT] WARN: problems with platform =
ojb.broker.platforms.PlatformMySQLImpl:
ojb.broker.platforms.PlatformMySQLImpl
[DEFAULT] WARN: OJB will use PlatformDefaultImpl instead



Do you have any idea of what's might the problem be?

Besides this, how can I make OJB perform faster?


Thanks in advance!

Ricardo Arguello

Re: [OJB-developers] problems with platform ojb.broker.platforms.PlatformMySQLImpl

[Jakob B. <jbr...@ho...>]

hi ricardo,

everything is fine, ojb cannot find a platform for mysql and writes it to
the console.
if you load the zip from my last post, you'll have a platform for mysql.

hth jakob

----- Original Message -----
From: "Ricardo Argüello" <ri...@ya...>
To: "objectbridge" <obj...@li...>
Sent: Monday, February 18, 2002 4:39 PM
Subject: [OJB-developers] problems with platform
ojb.broker.platforms.PlatformMySQLImpl


Hello,

I'm using MySQL. I upgraded to OJB 0.7.343, and now I get this message when
I initialize it:

[BOOT] INFO: OJB.properties:
file:/C:/Java/Tomcat401/webapps/charlie-dev/WEB-INF/classes/OJB.properties
[DEFAULT] WARN: problems with platform
ojb.broker.platforms.PlatformMySQLImpl:
ojb.broker.platforms.PlatformMySQLImpl
[DEFAULT] WARN: OJB will use PlatformDefaultImpl instead
[DEFAULT] WARN: problems with platform
ojb.broker.platforms.PlatformMySQLImpl:
ojb.broker.platforms.PlatformMySQLImpl
[DEFAULT] WARN: OJB will use PlatformDefaultImpl instead

It looks like everything is working right, I just wanted to know what is
this message about.

Thanks in advance,

Ricardo Arguello


_______________________________________________
Objectbridge-developers mailing list
Obj...@li...
https://lists.sourceforge.net/lists/listinfo/objectbridge-developers

[OJB-developers] problems with platform ojb.broker.platforms.PlatformMySQLImpl

[<ri...@ya...>]

Hello,

I'm using MySQL. I upgraded to OJB 0.7.343, and now I get this message =
when I initialize it:

[BOOT] INFO: OJB.properties: =
file:/C:/Java/Tomcat401/webapps/charlie-dev/WEB-INF/classes/OJB.propertie=
s
[DEFAULT] WARN: problems with platform =
ojb.broker.platforms.PlatformMySQLImpl: =
ojb.broker.platforms.PlatformMySQLImpl
[DEFAULT] WARN: OJB will use PlatformDefaultImpl instead
[DEFAULT] WARN: problems with platform =
ojb.broker.platforms.PlatformMySQLImpl: =
ojb.broker.platforms.PlatformMySQLImpl
[DEFAULT] WARN: OJB will use PlatformDefaultImpl instead

It looks like everything is working right, I just wanted to know what is =
this message about.

Thanks in advance,

Ricardo Arguello

[OJB-developers] OJB enhancements to 07.343

[Jakob B. <jbr...@ho...>]

hi,

the attached zip contains several enhancements to version 07.343:

- deferred loading (lazy) for 1:1 relationships
- wasNull when reading from ResultSet
- platform cacheing
- platform functions for setObject(), setNull()
- a MySql platform to fix setObject for Types.BIT
- StatementManager bindInsert and bindUpdate use platform functions now

the most important feature is deferred loading for 1:1 relationships. it's
based on DynamicProxies and thus requires you to implement an interface for
the target side of the relationship (referenced.class). to enable it, use
<proxyReference>true</proxyReference> in ReferenceDescriptor:

<ReferenceDescriptor id="1">
    <rdfield.name>partner</rdfield.name>
    <referenced.class>brj.ojb.Person</referenced.class>
    <fk_descriptor_ids>9</fk_descriptor_ids>
    <proxyReference>true</proxyReference>
</ReferenceDescriptor>

for consistency i also renamed <proxy> to <proxyCollection> for
CollectionDescriptor.

jakob

Re: [OJB-developers] StatementManager bindInsert, bindUpdate

[Jakob B. <jbr...@ho...>]

hi florian,

i really think modifiying the driver is the way to go here
because there's no other type than BIT to model a Boolean in java.sql.Types.

jakob

----- Original Message -----
From: "Florian Bruckner" <bf...@fl...>
To: "Jakob Braeuchi" <jbr...@ho...>
Cc: <obj...@li...>
Sent: Friday, February 15, 2002 11:28 AM
Subject: RE: [OJB-developers] StatementManager bindInsert, bindUpdate


>
> > i'm using it as a boolean.
> > according to the mysql doc BIT, BOOL and CHAR(1) are synonyms, but the
> > driver does not know BIT.
>
> Thats what I thought. I think the problem is really within your mapping,
the
> old code just covered an inconsistency within it. Try to modify the type
so
> it is regocnised by the JDBC-Driver.
>
> >
> > maybe this is an additional point for the DatabasePlatform ?
>
> Of course you could also modify the JDBC-Driver ;-)
>
> >
> > jakob
> >
>
> Florian
>
>

RE: [OJB-developers] StatementManager bindInsert, bindUpdate

[Florian B. <bf...@fl...>]

> i'm using it as a boolean.
> according to the mysql doc BIT, BOOL and CHAR(1) are synonyms, but the
> driver does not know BIT.

Thats what I thought. I think the problem is really within your mapping, the
old code just covered an inconsistency within it. Try to modify the type so
it is regocnised by the JDBC-Driver.

>
> maybe this is an additional point for the DatabasePlatform ?

Of course you could also modify the JDBC-Driver ;-)

>
> jakob
>

Florian

[OJB-developers] CVS is up again!

[Mahler T. <tho...@it...>]

Hi all,

I set up the CVS at sourceforge again.

The CVS entry page is here: http://sourceforge.net/cvs/?group_id=13647

The active module is called ojb-1-0. You can view it at:
http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/objectbridge/ojb-1-0/

With 
cvs -z3
-d:pserver:ano...@cv...:/cvsroot/objectbridge
co ojb-1-0 
you can checkout the latest snapshot.
(When prompted for a password for anonymous, simply press the Enter key)

Those who wish to check in code should contact me and send me their
SourceForge account so that I can add them to the developer list.

We need some strict rules to avoid problems with CVS. I want to have have
basic guidelines similar to the Jakarta guidelines
(http://jakarta.apache.org/site/guidelines.html)

cu,

Thomas

[OJB-developers] AW: a couple questions

[Mahler T. <tho...@it...>]

Hi Matthew,

> -----Urspr=FCngliche Nachricht-----
> Von: Matthew Baird [mailto:ma...@so...]
> Gesendet: Donnerstag, 14. Februar 2002 18:43
> An: 'Mahler Thomas'
> Betreff: a couple questions
>=20
>=20
> when you are loading an object that has a relationship to=20
> many objects (a
> one to many relationship), the sql that you generate to load,=20
> what does it
> look like?

You can enable tracing of SQL statements in the OJB.properties file by
setting ojb.broker.accesslayerSqlGenerator.LogLevel=3DDEBUG

>=20
> Let's say A has relations to many B's.
>=20
> In castor, the query that is generated includes all the A=20
> attributes, and
> the foreign key from B that refers to A. so
>=20
> SELECT A.id, A.foo, A.bar, B.fk_to_A FROM A, B WHERE ....
>=20
> what this results in is you get a resultset back with=20
> multiple repeated
> rows. How does objectbridge do it?
>=20
> Also....
>=20
> when I do a query in objectbridge and get many results, do I=20
> materialize
> those objects from an underlying resultset as I need them, or does
> objectbridge do all the object materialization up front? I=20
> looked at the
> code and it looked like the former, but I wanted to get confirmation.
>=20

Maybe my English is too bad. I don't exactly understand your question.

The process for loading an A with a Collection of Bs works like follows
(simplified version):
1. generate SQL for materialization of A (primitive Attributes only):
   "SELECT A.id, A.foo, A.bar FROM A WHERE ...."
2. retrieve all 1-1 references
3. retrieve all 1-n references
3a. if the B collection descriptor is marked as lazy no further
materialization happens but a CollectionProxy is placed in the B =
collection
attribute. This allows loading on demand.
3b. If the B collection descriptor is not lazy a getCollectionByQuery =
is
performed to retrieve the collection attribute.
3b1. This query looks like "SELECT B.id, B.foo, B.bar, B.fk_to_A FROM =
B, A
WHERE B.fk_to_A =3D A.id". OJB retrieve a ResultSet based on this =
query. OJB
use RsIterators to read all B instance into the collection attribute.
3b2. If the Class B is configured to use instance proxies the B objects =
are
not fully materialized from the current row. Only lightweight proxies =
are
generated.
3b.3. If no proxies are use Objects are read fully.

This concept allows for maximum laziness during the matreialization =
process.

But: OJB does currently not allow to perform just one large JOIN =
statement
to materialize large object nets from a single resultset. This would =
require
a major redesign.

I hope this answers some of your questions.

cu,

Thomas

> m
>=20

AW: AW: [OJB-developers] Base class queries on inheritance mapped to 2 tables

[Mahler T. <tho...@it...>]

Hi Dale,

> -----Urspr=FCngliche Nachricht-----
> Von: Dal...@bd... [mailto:Dal...@bd...]
> Gesendet: Freitag, 15. Februar 2002 02:52
> An: Mahler Thomas
> Betreff: Re: AW: [OJB-developers] Base class queries on inheritance
> mapped to 2 tables
>=20
>=20
>=20
> Hi Thomas.
>=20
> I did some tracing through in the 0.7.343 code and finally=20
> got my two-table
> inheritance test working. I wasn't aware that in order for=20
> two-table inheritance
> to work, the query must be on an interface rather than a=20
> concrete class. Once I
> created [and queried on] an interface, the test was successful.
>=20
> Having to query on interfaces, however, might turn out to be=20
> rather limiting for
> programmers working with legacy code. If a programmer *must*=20
> use concrete base
> classes, OJB won't work for them because=20
> getCollectionByQuery() and other
> methods only check extents for interfaces.
>=20

Mmh, OJB provides support for queries against interfaces AND against
Baseclasses!
If you want to query against a base clase you MUST declare which =
derived
classes are in the baseclasses extent in the repository.xml.
There are several testcases that check this behaviour.=20

If some special things do not work we need testcases to demonstrate the
failure.

> BTW, this is also why single table inheritance doesn't work.=20
> In the example I
> posted with a base class and descendent class with different=20
> numbers of fields,
> the exception in the RsIterator was caused because the=20
> SqlGenerator was
> generating a query for the Base class (a concrete class with=20
> only 3 fields). It
> did this because the broker's collection and iterator query=20
> methods don't read
> extents for non-interface classes. There weren't enough=20
> columns in the ResultSet
> when it came time to materialize the Descendent class (a=20
> concrete class with 4
> fields, 3 from Base + 1).

I added this bug to my list. this must be fixed!

>=20
> I've been thinking that there might be two possible fixes for=20
> this. One fix
> would be to modify SqlGenerator.getListOfColumns to traverse=20
> extents. I think
> this would be more of a hack, though.=20

I agree!

>The second fix might be=20
> to rewrite the get
> collection/iterator functions to ignore the difference=20
> between interfaces and
> concrete classes and always traverse extents.

Yes this would match with my original extent concepts.

> Finally, to=20
> really make the code
> robust, Criteria (or Query) could be modified so that a user=20
> could specify a
> query for a base class and descendents, or just the base=20
> class. I don't know why
> someone would want to just query for base instances and not=20
> descendents, but you
> never know.

We already have this flexibility by modifying ClassDescriptors at =
runtime!

>=20
> I'll probably start trying out some of these changes myself.=20
> If you have any
> advice or input on this, I'd like to hear it.
>=20

IMHO the best thing is to preserve the original notion of extents. Thus =
I
prefer the second solution you mention!

regarding collaboration. I can add you to the OJB list of developers so =
that
you could check in your code directly into the cvs repository!=20
Please tell me your SourceForge account if you want to use CVS =
directly!

cu,

Thomas


> Dale Davis
>=20
>=20

Re: [OJB-developers] StatementManager bindInsert, bindUpdate

[Jakob B. <jbr...@ho...>]

hi,

i'm using it as a boolean.
according to the mysql doc BIT, BOOL and CHAR(1) are synonyms, but the
driver does not know BIT.

maybe this is an additional point for the DatabasePlatform ?

jakob

----- Original Message -----
From: "Florian Bruckner" <bf...@fl...>
To: "Jakob Braeuchi" <jbr...@ho...>;
<obj...@li...>
Sent: Thursday, February 14, 2002 9:19 PM
Subject: RE: [OJB-developers] StatementManager bindInsert, bindUpdate


> Hi,
>
> the type in bindInsert is to be able to insert BLOB/CLOB values. At least
> the informix jdbc driver needs this hint. The reason why it isn't in
> bindUpdate is that I missed it when I sent Thomas the patch for BLOB/CLOB
> support.
>
> I'm curious, why do you want to insert/update a BIT when it doesn't exist
in
> mysql?
>
> regards,
> Florian
>
>
> _______________________________________________
> Objectbridge-developers mailing list
> Obj...@li...
> https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
>

RE: [OJB-developers] StatementManager bindInsert, bindUpdate

[Florian B. <bf...@fl...>]

Hi,

the type in bindInsert is to be able to insert BLOB/CLOB values. At least
the informix jdbc driver needs this hint. The reason why it isn't in
bindUpdate is that I missed it when I sent Thomas the patch for BLOB/CLOB
support.

I'm curious, why do you want to insert/update a BIT when it doesn't exist in
mysql?

regards,
Florian

[OJB-developers] StatementManager bindInsert, bindUpdate

[Jakob B. <jbr...@ho...>]

hi,

why are the parameters bound differently in bindInsert and bindUpdate ?

bindInsert:
if (val != null)
{
    stmt.setObject(i + 1, val, JdbcAccess.getSqlTypeAll(cld, i));
    //stmt.setObject(i + 1, val);
}
else

bindUpdate:

Object val = values[i];
if (val != null)
    stmt.setObject(index, val);
else

the new setObject with Type used in bindInsert produces an exception for
Types.BIT in mySql because this type is not supported in
setObject(obj,type). the setObject without the type works perfectly.
what was the reason to change setObject in 07.343 ? and why is it only in
bindInsert ?

thanks jakob

Re: [OJB-developers] Detecting and mapping null Integer values

[Jakob B. <jbr...@ho...>]

hi,

i experimented with mySql. they do not have a real boolean, so when using
rs.getObject() the result is either a Byte or a String leading to an
exception in PersistentField::set(). when using getBoolean() the driver
converts the string ('f' in this case) to a Boolean (false).

jakob

----- Original Message -----
From: "Mahler Thomas" <tho...@it...>
To: "'Darren Syzling'" <Dar...@cw...>;
<obj...@li...>
Sent: Thursday, February 14, 2002 12:16 PM
Subject: AW: [OJB-developers] Detecting and mapping null Integer values


Hi all,

I prefer the wasNull() solution as getObject() is Problematic with several
JDBC drivers...
I will put this on my todo list !

thanks,

Thomas

> -----Ursprüngliche Nachricht-----
> Von: Darren Syzling [mailto:Dar...@cw...]
> Gesendet: Donnerstag, 14. Februar 2002 10:45
> An: obj...@li...;
> tho...@ho...
> Betreff: Re: [OJB-developers] Detecting and mapping null
> Integer values
>
>
> It appears to me there are two choices:
>
> - wasNull
>
> - getObject using a cast, is there any reason this wouldn't
> work ?  For example:
>
> case Types.INTEGER :
> {
>   result = (Integer)rs.getObject(columnId);
>   break;
> }
>
> getObject will return a null reference if the column value is null.
>
>
>
> Darren
>
>
>
> |--------+----------------------->
> |        |          "Jakob       |
> |        |          Braeuchi"    |
> |        |          <jbraeuchi@ho|
> |        |          tmail.com>   |
> |        |                       |
> |        |          02/13/02     |
> |        |          07:44 PM     |
> |        |                       |
> |--------+----------------------->
>
> >-------------------------------------------------------------
> ---------------|
>   |
>                  |
>   |       To:     "Thomas Mahler"
> <tho...@ho...>, Darren          |
>   |       Syzling/London/CWB@CWB
>                  |
>   |       cc:
> obj...@li...                |
>   |       Subject:     Re: [OJB-developers] Detecting and
> mapping null Integer |
>   |       values
>                  |
>
> >-------------------------------------------------------------
> ---------------|
>
>
>
>
> hi thomas,
>
> what about using wasNull of ResultSet ?
>
> /**
> * Reports whether
> * the last column read had a value of SQL <code>NULL</code>.
> * Note that you must first call one of the <code>getXXX</code> methods
> * on a column to try to read its value and then call
> * the method <code>wasNull</code> to see if the value read was
> * SQL <code>NULL</code>.
> *
> * @return <code>true</code> if the last column value read was SQL
> * <code>NULL</code> and <code>false</code> otherwise
> * @exception SQLException if a database access error occurs
> */
> boolean wasNull() throws SQLException;
>
> hth jakob
>
> ----- Original Message -----
> From: "Thomas Mahler" <tho...@ho...>
> To: "Darren Syzling" <Dar...@cw...>
> Cc: <obj...@li...>
> Sent: Wednesday, February 13, 2002 8:09 PM
> Subject: Re: [OJB-developers] Detecting and mapping null
> Integer values
>
>
> > Hi Darren,
> >
> > Darren Syzling wrote:
> >
> > > How can I detect null values for Integer, Long, Double
> etc Java class
> attributes
> > > ?  Let's say we're mapping an object which has the
> following attributes:
> > >
> > > class Test
> > > {
> > >   Integer id;
> > >   String name;
> > >   Integer sales;
> > > }
> > >
> > >
> > > Let's assume that both name and sales can be null.  When
> retrieving this
> object
> > > from the database using the PersistenceBroker the String
> reference will
> be null
> > > but the sales reference will in fact refer to an Integer
> object with a
> zero
> > > value.  If zero is within the valid range how can we
> detect that the
> value is
> > > actually null.
> > >
> > > This appears to boil down to:
> JdbcAccess.getObjectFromColumn.  The code
> to
> > > convert a string looks like:
> > >
> > > case Types.VARCHAR:
> > >   result = rs.getString(columnId);
> > >   break;
> > >
> > > If the string value is null getString will return a null
> reference.  But
> for
> > > Integer (and other classes) the following is used:
> > >
> > > case Types.INTEGER:
> > >   result = new Integer(rs.getInt(columnId));
> > >   break;
> > >
> >
> >
> >
> > I get your point. But: how should the above code look like to handle
> > your problem correctly? I have no idea.
> > If you (or somebody else) tell me how this section should
> look like I
> > will change it!
> >
> >
> > java.sql.ResultSet does not tell you that a column is NULL. It just
> > returns a 0. Of course this is wrong. But SUN specified it this way.
> > Or am I missing something? From the java.sql.ResultSet Source:
> >
> >      /**
> >       * Gets the value of the designated column in the current row
> >       * of this <code>ResultSet</code> object as
> >       * an <code>int</code> in the Java programming language.
> >       *
> >       * @param columnIndex the first column is 1, the
> second is 2, ...
> >       * @return the column value; if the value is SQL
> <code>NULL</code>,
> >       * the value returned is <code>0</code>
> >       * @exception SQLException if a database access error occurs
> >       */
> >      int getInt(int columnIndex) throws SQLException;
> >
> >
> > > getInt will return 0 for null and the an integer will be
> created with a
> zero
> > > value.
> > >
> > > The Conversion Strategy stuff appears too late in the day
> to make the
> > > conversion.
> >
> >
> > You are right, things are already on the wrong track at
> this point....
> >
> >  How is everybody else handling this or have I missed something ?
> >
> >
> > cu,
> >
> > Thomas
> >
> >
> > >
> > >
> > > Thanks
> > > Darren
> > >
> > >
> > >
> > >
> **************************************************************
> **************
> **************************************************************
> ************
> > > This e-mail has been prepared using information  believed  by  the
> author to be
> > > reliable and accurate, but Thales Information Systems
> Finance makes  no
> > > warranty  as to accuracy or completeness. In particular Thales
> Information
> > > Systems Finance does not  accept  responsibility  for
> changes  made to
> this
> > > e-mail after it was sent.  Any  opinions expressed in
> this document are
> those of
> > > the author and do  not  necessarily reflect the opinions
> of the company
> or its
> > > affiliates. They may be subject to change without notice.
> > > This  e-mail,  its  content  and any files transmitted with it are
> intended
> > > solely   for   the  addressee(s)  and  may  be legally  privileged
> and/or
> > > confidential. Access by any other party is unauthorised
> without the
> express
> > > written permission of the sender. If you have received
> this e-mail in
> error you
> > > may  not  copy  or use the contents, attachments or
> information in any
> way.
> > > Please  destroy  it and contact the sender via the Thales
> Information
> Systems
> > > Finance switchboard in London at +44  (0) 20 7650 0100 or
> via e-mail
> return.
> > > This message and any attachments have been scanned
> > > for viruses prior to leaving the originators network. The
> originator
> does not
> > > guarantee the security of this message and will not be
> responsible for
> any
> > > damages arising from any alteration of this message by a
> third party or
> as a
> > > result of any virus being passed on.
> > >
> **************************************************************
> **************
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> *************
> > >
> > >
> > >
> > > _______________________________________________
> > > Objectbridge-developers mailing list
> > > Obj...@li...
> > >
https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
> >
> >
> >
> >
>
>
>
>
> _______________________________________________
> Objectbridge-developers mailing list
> Obj...@li...
> https://lists.sourceforge.net/lists/listinfo/objectbridge-developers
>

_______________________________________________
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https://lists.sourceforge.net/lists/listinfo/objectbridge-developers





_______________________________________________
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Obj...@li...
https://lists.sourceforge.net/lists/listinfo/objectbridge-developers

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https://lists.sourceforge.net/lists/listinfo/objectbridge-developers

[OJB-developers] OJB and Informix

[Florian B. <bf...@fl...>]

Hi,

just wanted to report that I was able to run the junit test suite against an
informix database with just one error:

junit:
    [junit] .[BOOT] INFO: OJB.properties:
file:/C:/work/OJB/ojb-0.7.343-src/ojb-0.7.343/build/test/ojb/OJB.properties
    [junit] .....[DEFAULT] ERROR: after inserting an object it should be
equal to its re-read pendant expected:<Single quote 'article > but
was:<Single quote 'article>
    [junit] junit.framework.AssertionFailedError: after inserting an object
it should be equal to its re-read pendant expected:<Single quote 'article >
but was:<Single quote 'article>
    [junit] 	at junit.framework.Assert.fail(Assert.java:51)
    [junit] 	at junit.framework.Assert.failNotEquals(Assert.java:234)
    [junit] 	at junit.framework.Assert.assertEquals(Assert.java:68)
    [junit] 	at
test.ojb.broker.PersistenceBrokerTest.testEscaping(PersistenceBrokerTest.jav
a:423)
    [junit] 	at java.lang.reflect.Method.invoke(Native Method)
    [junit] 	at junit.framework.TestCase.runTest(TestCase.java:166)
    [junit] 	at junit.framework.TestCase.runBare(TestCase.java:140)
    [junit] 	at junit.framework.TestResult$1.protect(TestResult.java:106)
    [junit] 	at junit.framework.TestResult.runProtected(TestResult.java:124)
    [junit] 	at junit.framework.TestResult.run(TestResult.java:109)
    [junit] 	at junit.framework.TestCase.run(TestCase.java:131)
    [junit] 	at junit.framework.TestSuite.runTest(TestSuite.java:173)
    [junit] 	at junit.framework.TestSuite.run(TestSuite.java:168)
    [junit] 	at junit.framework.TestSuite.runTest(TestSuite.java:173)
    [junit] 	at junit.framework.TestSuite.run(TestSuite.java:168)
    [junit] 	at junit.textui.TestRunner.doRun(TestRunner.java:74)
    [junit] 	at junit.textui.TestRunner.start(TestRunner.java:234)
    [junit] 	at junit.textui.TestRunner.main(TestRunner.java:112)
    [junit] F...................................
    [junit] .....
    [junit] Time: 16,806
    [junit] There was 1 failure:
    [junit] 1)
testEscaping(test.ojb.broker.PersistenceBrokerTest)junit.framework.Assertion
FailedError: after inserting an object it should be equal to its re-read
pendant expected:<Single quote 'article > but was:<Single quote 'article>
    [junit] 	at
test.ojb.broker.PersistenceBrokerTest.testEscaping(PersistenceBrokerTest.jav
a:494)
    [junit]
    [junit] FAILURES!!!
    [junit] Tests run: 46,  Failures: 1,  Errors: 0
    [junit]


I had to do some small modifications to db-setup.sql and repository.xml,
attached are the modified files of version 0.7.343.

MfG,

Florian

AW: [OJB-developers] Detecting and mapping null Integer values

[Mahler T. <tho...@it...>]

Hi Jakob,

After having a short look at the code I believe that you are right!
I'll put it on my todo list!

thanks,

Thomas

> -----Urspr=FCngliche Nachricht-----
> Von: Jakob Braeuchi [mailto:jbr...@ho...]
> Gesendet: Donnerstag, 14. Februar 2002 08:50
> An: Thomas Mahler
> Cc: obj...@li...
> Betreff: Re: [OJB-developers] Detecting and mapping null=20
> Integer values
>=20
>=20
> hi thomas,
>=20
> i think the method set() of PersistentField could be =20
> streamlined a lot when
> using f.set(obj,value) instead of the if-else-cascade.
>=20
> public void set(Object obj, Object value) throws=20
> IllegalAccessException,
> IllegalArgumentException
> {
>     boolean before =3D getField().isAccessible();
>     AccessController.doPrivileged(new SetAccessibleAction());
>     Field f =3D getField();
>     Class type =3D f.getType();
>     try
>     {
>     f.set(obj,value);
>     }
>     catch (IllegalArgumentException ex)
>     {
>         getField().setAccessible(before);
>         LoggerFactory.getDefaultLogger().error(ex);
>         LoggerFactory.getDefaultLogger().error("field: " +=20
> fieldname + ",
> type: " + type);
>         LoggerFactory.getDefaultLogger().error("value: " +=20
> value + ", type:
> " + value.getClass());
>         throw ex;
>     }
>     getField().setAccessible(before);
> }
>=20
> jakob
>=20
> ----- Original Message -----
> From: "Thomas Mahler" <tho...@ho...>
> To: "Darren Syzling" <Dar...@cw...>
> Cc: <obj...@li...>
> Sent: Wednesday, February 13, 2002 8:09 PM
> Subject: Re: [OJB-developers] Detecting and mapping null=20
> Integer values
>=20
>=20
> > Hi Darren,
> >
> > Darren Syzling wrote:
> >
> > > How can I detect null values for Integer, Long, Double=20
> etc Java class
> attributes
> > > ?  Let's say we're mapping an object which has the=20
> following attributes:
> > >
> > > class Test
> > > {
> > >   Integer id;
> > >   String name;
> > >   Integer sales;
> > > }
> > >
> > >
> > > Let's assume that both name and sales can be null.  When=20
> retrieving this
> object
> > > from the database using the PersistenceBroker the String=20
> reference will
> be null
> > > but the sales reference will in fact refer to an Integer=20
> object with a
> zero
> > > value.  If zero is within the valid range how can we=20
> detect that the
> value is
> > > actually null.
> > >
> > > This appears to boil down to:=20
> JdbcAccess.getObjectFromColumn.  The code
> to
> > > convert a string looks like:
> > >
> > > case Types.VARCHAR:
> > >   result =3D rs.getString(columnId);
> > >   break;
> > >
> > > If the string value is null getString will return a null=20
> reference.  But
> for
> > > Integer (and other classes) the following is used:
> > >
> > > case Types.INTEGER:
> > >   result =3D new Integer(rs.getInt(columnId));
> > >   break;
> > >
> >
> >
> >
> > I get your point. But: how should the above code look like to =
handle
> > your problem correctly? I have no idea.
> > If you (or somebody else) tell me how this section should=20
> look like I
> > will change it!
> >
> >
> > java.sql.ResultSet does not tell you that a column is NULL. It just
> > returns a 0. Of course this is wrong. But SUN specified it this =
way.
> > Or am I missing something? From the java.sql.ResultSet Source:
> >
> >      /**
> >       * Gets the value of the designated column in the current row
> >       * of this <code>ResultSet</code> object as
> >       * an <code>int</code> in the Java programming language.
> >       *
> >       * @param columnIndex the first column is 1, the=20
> second is 2, ...
> >       * @return the column value; if the value is SQL=20
> <code>NULL</code>,
> >       * the value returned is <code>0</code>
> >       * @exception SQLException if a database access error occurs
> >       */
> >      int getInt(int columnIndex) throws SQLException;
> >
> >
> > > getInt will return 0 for null and the an integer will be=20
> created with a
> zero
> > > value.
> > >
> > > The Conversion Strategy stuff appears too late in the day=20
> to make the
> > > conversion.
> >
> >
> > You are right, things are already on the wrong track at=20
> this point....
> >
> >  How is everybody else handling this or have I missed something ?
> >
> >
> > cu,
> >
> > Thomas
> >
> >
> > >
> > >
> > > Thanks
> > > Darren
> > >
> > >
> > >
> > >
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