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From Joerg von Frantzius <joerg.von.frantz...@artnology.com>
Subject Re: multiple databases one PM/TX
Date Mon, 05 Nov 2007 09:43:05 GMT
Hi Erik,

OK now I got it, you want to support fields within the same PC class to
be persisted to different datasources, right?

Erik Bengtson schrieb:
> Jorg,
>
> An example:
>
> Class product
>
> Field name ; //oracle
> Field price ; //erp
> Field instock ; //erp
>
> With multiple databases feature, you can load an object distributed in multiples databases.
As Eric said we will not reinvent JTA.
>
> Each implementation can use JTA to support transactions with multiple datasources, but
can use any other mechanism (not defined). JPOX is pluggable and enabled to accept any jta
implementation.  
>
> If you don't provide an external jta implementation, JPOX will use its internal implementation.
> --   BlackBerry® from Mobistar    ---
>
> -----Original Message-----
> From: Joerg von Frantzius <joerg.von.frantzius@artnology.com>
>
> Date: Mon, 05 Nov 2007 10:28:55 
> To:jdo-dev@db.apache.org
> Cc:jdo-experts-ext@sun.com
> Subject: Re: multiple databases one PM/TX
>
>
> Hi Erik,
>
> there is one thing that I don't understand about this proposed feature
> (which may be just me not seeing the obvious point of course :)
>
> Running 2PC on multiple data sources is handled already by J2EE
> implementations, and, as far as I recall, there are also libraries
> available that provide a JTA without a full blown J2EE server. Why would
> you want to duplicate this already existing and available functionality
> in JDO?
>
> Regards,
> Jörg
>
> Erik Bengtson schrieb:
>   
>> In JPOX we are implementing the access to multiple datastores within a single
>> PM/TX. If not too late, I’m wonder if you like to hear a proposal to
>> standardize the configuration of the “jdoconfig” and jdo metadata to be able
to
>> handle this scenario. It may sound overkill, but IMO is a major advance over
>> JPA.
>>
>> To introduce the subject, the goal is to handle persistence in multiple
>> databases (e.g. derby, oracle, DB4O, Versant, XML) within a single JDO
>> transaction/ single PM. From the user point of view, there are two items that
>> must be configured, jdo metadata, jdo configuration, in which would be part of
>> this proposal, so I show below an example of the configurations:
>>
>> /jdoconfig/ sequence unbounded PMF
>> /jdoconfig/ sequence unbounded Resource
>>
>> /PMF/
>> /PMF/@Class
>> /PMF/@TransactionTimeout
>> /PMF/@...
>> /Resource/
>> /Resource/@Name
>> /Resource/Connection Settings/
>> /Resource/Connection Settings/@ConnectionFactoryName
>> /Resource/Connection Settings/@ConnectionClientID
>> /Resource/Connection Settings/@ReadOnly
>> /Resource/Connection Settings/@...
>> /Resource/Transaction/
>> /Resource/Transaction/@TwoPhaseCommit
>> /Resource/Transaction/@Timeout
>>
>> ConnectionClientID
>> ----------------------------
>> ConnectionClientID is the identifier for the connection. Some databases such as
>> Oracle use this to identify the end user (not the connection user).
>> ConnectionClientID would accept the values:
>>
>> 1 - CredentialMapping - the CredentialMapping takes the principal of the running
>> application and sets it as client id - eg. ConnectionClientID=CredentialMapping
>> 2 - Identity – the client id is taken from the id right after the Identity word
>> - eg. ConnectionClientID=Identity:MyUser
>>
>> ReadOnly
>> ----------------------------
>> ReadOnly (accepts true, false) will block write operations to this connection
>>
>> TwoPhaseCommit
>> --------------------------
>> Two options:
>>
>> 1 – LastLoggingResource - If the resource is non XA, push down this resource in
>> commit order.
>> 2 – Emulated – Emulates non XA protocol. Heuristics errors could happen
>>
>> Example:
>>
>> <jdoconfig>
>>
>> <pmf name=”snowdog” default-resource=”Oracle”>
>> </pmf>
>>
>> <resource name=”ERP”>
>> <connection connectionfactoryname=”BSCS_Hot”/>
>> </resource>
>>
>> <resource name=”PeopleSoft”>
>> <connection connectionfactoryname=”PS_Onyx”/>
>> </resource>
>>
>> <resource name=”Oracle”>
>> <connection connectionfactoryname=”ORA_Vinci”
>> connection-client-id=”CredentialMapping”/>
>> <transaction two-phase-commit=”LLR” timeout=”30”/>
>> </resource>
>>
>> <resource name=”Xml”>
>> <connection readonly=”true”/>
>> <extension>
>> <jpox:xml file=”file:/usr/home/myxml.xml”/>
>> </extension>
>> </resource>
>>
>>
>> </jdoconfig>
>>
>> <jdo>
>> <package>
>> <class name=”Invoice” resource=”ERP”/>
>> <class name=”ClassData”/> <!-- uses default-resource -->
>> <class name=”Person” resource=”PeopleSoft”/>
>> <class name=”ReferenceData” resource=”Xml”/>
>> </package>
>> </jdo>
>>
>>
>>
>>
>> Quoting Michelle Caisse <Michelle.Caisse@sun.com>:
>>
>>   
>>     
>>> Hi,
>>>
>>> We will have our regular meeting Friday, October 26 at 9 am PDT to
>>> discuss JDO TCK issues and status.
>>>
>>> Dial-in numbers are:
>>> 866 230-6968   294-0479#
>>> International: +1 865 544-7856
>>>
>>> Agenda:
>>>
>>> 1. Subquery spec update
>>> 2. Other issues
>>>
>>> Action Items from weeks past:
>>>
>>> [Oct 12 2007] AI Michael take a look at subquery tck tests.
>>> https://issues.apache.org/jira/browse/JDO-446
>>>
>>> [Sep 14 2007] AI Matthew provide examples for 8.6.1.1 jdoconfig.xml.
>>>
>>> [June 22 2007] AI Craig discuss svn:eol-style on email.
>>>
>>> [June 22 2007] AI Craig write a proposal on annotation overrides for
>>> the expert group.
>>>
>>> [May 25 2007]  AI everyone Download the Grails demo from grails.org  and
>>> check it out. Also look at Grails/Groovy ExpandoMetaClass that  has the
>>> magic to avoid reflection and enhancement.
>>>
>>> [May 25 2007] AI Matthew Adams prepare a proposal with just the  basics
>>> of schema synchronization with jdo and orm metadata.
>>>
>>> [May 18 2007] AI Craig update http://wiki.apache.org/jdo/
>>> CurrentDevelopment wiki page
>>>
>>> [Apr 27 2007] AI Craig review Query API and send email to experts.
>>>
>>> [Apr 27 2007] AI Erik file a JIRA regarding JPA style transactions  and
>>> attach his discussion document to it.
>>>
>>> [Mar 9 2007] AI Craig: Update the spec to require that the key of the
>>> listener is the class name of the listener, for consistency with
>>> proposed xml..
>>>
>>> [Mar 2 2007] AI Craig: update the JDOHelper class to include a string
>>> constant "META-INF/jdo.xml" and a new method
>>> getPersistenceManagerFactory taking no arguments.
>>>
>>> [Aug 11 2006] AI Craig propose some semantics for behavior if user
>>> tries to add to a list where the ordering element is incorrect.
>>>
>>> [Jul 14 2006] AI: Erik document 220 annotations that don't have a
>>> corresponding JDO concept.
>>>
>>> [Jun 23 2006]  AI  Martin look at what Hibernate and TopLink support
>>> for Enum types. In progress.
>>>
>>> [Apr 14 2006] AI Craig: update the roadmap for JDO. In progress.
>>>
>>> [Nov 4 2005] AI Martin: Update Martin's wiki with discusion of JDK   1.5
>>> issues. In progress
>>>
>>> [Sep 2 2005] AI: To recruit members, update the web site. Articles  on
>>> TheServerSide directing attention to the site. T-shirts, logo.    AI:
>>> Craig write a ServerSide article.
>>>
>>> -- Michelle
>>>
>>>     
>>>       
>>
>>
>>
>>   
>>     
>
>
>   


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