Re: AW: AW: Multiple Databases within the same application

Guys,

A quick email since I only have a minute right now.

Keel can handle multiple conmnections to multiple databases, even if they are
of different types.  I am using HsqlDB and Oracle concurrently.

The way you do that is to define a <jdbc> elelemnt for the type/connection
(i.e. this is where the JDBC driver definition and connection info go), follow
the example of <jdbc id="keel-dbpool" ... > and create <jdbc
id="second-dbpool">, <jdbc id="third-dbpool">.

Copy the right "*-dbtype" definition for your DB from the sample-conf
directory, and change the id="keel-dbtype" to "oracle-dbtype" for instance. 

Then define a <default-persistent id="second-db" ....> <default-persistent
id="third-db"  .....>.  Each default-persistent should have a nested <dbpool
...> element to pick from the <jdbc > definitions above, and a <dbtype ...>
element to tell Keel what type of DB (SQL syntax variations) it is.

Then you lookup:

PersistentFactory pf =
(PersistentFactory)req.getService(PersistentFactory.ROLE,
id-of-default-persistent);

HTH,
Shash

PS: Here's an example for Oracle.

	<jdbc id="sfpman-dbpool" activation="request">
		<pool-controller max="10" maxStrict="true" blocking="true" timeout="-1"
			trim-interval="60000" auto-commit="true"
			connection-class="org.apache.avalon.excalibur.datasource.JdbcConnection"
			>
		<keep-alive disable="false">select 1</keep-alive>
		</pool-controller>
		<driver>oracle.jdbc.driver.OracleDriver</driver>
		<!-- example: <dburl>jdbc:oracle:thin:@localhost:1521:KEEL</dburl> -->
		<dburl>jdbc:oracle:thin:@ora-dev-db1:1522:OATST</dburl>
		<!-- example:  <user>Scott</user> -->
		<user>WRNSFP</user>
		<!-- example: <password>tiger</password> -->
		<password>WRNSFP</password>
	</jdbc>

	<default-persistent id="sfpman" name="default" security="default"
logger="persist-default">
    	<dbpool>sfpman-dbpool</dbpool>
    	<dbtype>oracle-dbtype</dbtype>
 

> You can use it as a load balancer, but it's also possible to 
> "partition" your database... that means you can put some tables on 
> one database and some on others... they call this RAIDb (Redundant 
> Array of Inexpensive Databases).
> 
> Look in the features section of this 
> (http://www.objectweb.org/wws/d_read/marketing/public/projects/C-
> JDBC.pdf) document...
> 
> -----Ursprüngliche Nachricht-----
> Von: [email protected] [mailto:[email protected]]
> Gesendet: Dienstag, 23. März 2004 16:15
> An: user-6VIttnCrOeJXNEnpj1eHPNi2O/[email protected]
> Betreff: Re: AW: [Keel User] Multiple Databases within the same application
> 
> I'm not sure that c-jdbc does what you're wanting.  Isn't it more of 
> a load-balancer? 
> 
> It's a pretty neat piece of software though!   
> 
> Please respond to user-6VIttnCrOeJXNEnpj1eHPNi2O/[email protected] 
> Sent by:        user-keelframework.org-admin-rI8AND0JKYOgdSakss0wQjfEH8FBEnyy@public.gmane.org 
> To:        <user-6VIttnCrOeJXNEnpj1eHPNi2O/[email protected]> 
> cc:         
> 
> Subject:        AW: [Keel User] Multiple Databases within the same 
> application 
> 
> Salut,
> 
> I'm also interested in this scenario and it could be done with keel.
> 
> Though, another solution would be to use c-jdbc by objectweb. It's a 
> jdbc driver that hides multiple databases behind a single (virtual) database.
> 
> Pro:
> - it's only jdbc...
> 
> Con:
> - I think with the persistence service you can only handle ONE 
> database TYPE, i. e. several Oracle instances, but no mix of 
> different database products... BUT: might be possible with a 
> "generic sql" configuration.
> 
> I'm going to explore this in the next days... maybe I'll be able to 
> say more about it...
> 
> Aleks
> 
> -----Ursprüngliche Nachricht-----
> Von: Hagerty, Timothy CIV NAVSAFECEN, 52D [mailto:[email protected]]
> Gesendet: Dienstag, 23. März 2004 15:52
> An: user-keelframework.org-rI8AND0JKYOgdSakss0wQjfEH8FBEnyy@public.gmane.org
> Betreff: [Keel User] Multiple Databases within the same application
> 
> Hello All, 
> I have a question about multiple database connections. 
> I have 3 separate database connections going to 3 different 
> databases. When I use the following code: PersistentFactory pf = 
> (PersistentFactory) request.getService(PersistentFactory.ROLE,       
>                                          request.getDomain());   I 
> get a connection to the first jdbc connection listed within the 
> merged.config file. How do I set one of those connections apart from 
> the other 2 as the default connection when I use the code: 
> request.getDomain()? Thanks, Tim _______________________________________________
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