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From John Dunne <imir...@alldunne.com>
Subject Re: multiple databases and addDescendingOrderByColumn
Date Fri, 31 Mar 2006 16:23:10 GMT
Thanks for replying Greg. I should have asked 'can I have a single 
application that accesses multiple SQL DB's using a single set of Torque 
classes'. I'll go ahead as you advised and report back what I find on 

Thanks for your time,

Greg Monroe wrote:

>Depends on what you mean by "work for".  If you mean
>something like: Can I have multiple applications (e.g.
>separate webapps) that use the same code to access different
>SQL Server Databases.  The answer is yes.
>The thing to understand here is that Torque's Database
>name is simply a key used to logically tie various Torque
>related items together. It has nothing to do with the SQL
>server Database name except to tie the JDBC info (which has
>the SQL DB name in it's URL) to the classes.
>In the case of multiple applications, you can just call
>Torque.init() in each application with different properties
>that point to whatever JDBC data source you want.  These can
>be defined in a static Torque.properties or be dynamically
>generated/modified by your application.
>If you mean, can I have a single application that accesses
>multiple SQL DB's using a single set of Torque classes, the
>answer is "probably, but you'll have to test it..". 
>The way to do this would be to handle the connections in
>your own code.  So instead of calling the no argument
>methods in the Record and Peer objects, (e.g.
>tableRecord.save(), TablePeer.doSelect()), you need to use
>the methods that have the Connection argument (e.g. 
>tableRecord.save(conn), TablePeer.doSelect(conn) ). The SQL
>connection is where the link between Torque and the SQL DB
>defined to JDBC are tied together.
>I say test because this is all theoretical and not a case that
>has had a lot of usage to shake out any bugs.
>FWIW, one way that you might use Torque to help you manage your
>connections is to define the different SQL DB's in the Torque
>properties JDBC settings with different Torque Database names.
>You should then be able to use the Torque.getConnection(dbName)
>method to get pooled connections to pass to the various methods.
>Remember that you'll still have to close these connections in
>your code.
>Good luck.
>>-----Original Message-----
>>From: John Dunne [mailto:imirish@alldunne.com] 
>>Sent: Friday, March 31, 2006 3:41 AM
>>To: Apache Torque Users List
>>Subject: multiple databases and addDescendingOrderByColumn
>>Is it possible to create a set of torque class files (from a 
>>file) that will work for multiple copies of schematically (?) 
>>databases? The problem I have is a nullpointerexception 
>>whenever I call 
>>addDescendingOrderByColumn on the database other than the one 
>>in the name property of the database xml element in schema.xml.
>>For example
>>      Criteria crit = new Criteria(databasename);
>>      crit.addDescendingOrderByColumn(TablenamePeer.STARTTIME);
>>      List l = TablenamePeer.doSelect(crit);
>>will generate a null pointer exception if 
>>databasename!=default db name 
>>i.e. the database name specified in the schema.xml. I've 
>>tried replacing 
>>the name property with * and comma deliminating all databases 
>>names, no 
>>success.... Any assistance would be gratefully welcome.
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