Re: [castor-dev] Can Castor map objects across different db servers?

[Richard Lawson]

Werner, I've seen you on this list for a while, so I hope that I'm not being set up  with a question you already know the answer to :-)

 

I'm not an ejb guru, but it seems that a transaction manager will wrap a transaction around the call to get the objects passed back by castor, but not the other way around.

An object is formed by castor, when the JDO creates a Database instance that's initialized for a given db. So it looks like a Database object would have to be initialized for two different physical databases if we were to query both at the same time. I don't see support for that in the API.

 

I'm guessing that you could utilize a transaction manager to have two JDOs get the data from two Databases and mappings, and then assemble them, but that seems like a lot of work. 

 

Is there a better way that you're aware of?

 

-richard

 

 

 

 

 

 

-----Original Message-----
From: Werner Guttmann [mailto:[EMAIL PROTECTED]
Sent: September 15, 2003 12:09 PM
To: [EMAIL PROTECTED]
Subject: Re: [castor-dev] Can Castor map objects across different db servers?

Richard,

If that's the case, how about the following scenario.

Let's assume that one is to deploy a web app/an ejb to an app server with transactions managed by either the
container or bean-managed. In such a scenario, where the app server is fully j2ee 1.3 compliant and provides a
transaction manager, would Castor support such an enviroment where the data resides in multiple databases?

Regards
Werner

On Mon, 15 Sep 2003 10:17:35 -0700, Richard Lawson wrote:

>Castor will try to get the parent and all the child objects defined in your
>mapping within a BEGIN TRAN ... COMMIT TRAN block. So this isn't possible.
>However, if your db supports distributed transactions, then you can create a
>view to the other db to get the child table you want. That works just fine.
>-richard
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
>Sent: September 15, 2003 7:36 AM
>To: [EMAIL PROTECTED]
>Subject: [castor-dev] Can Castor map objects across different db
>servers?
>
>
>Hi. I have a simple question. Can I have an object whose table resides on
>database server 1 be associated with an object whose table resides on
>database server 2? Has anyone done this? If yes, would it be possible to
>explain how or show me an example?
>
>Much appreciated.
>
>Isaac
>
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