Simon Allaway wrote:
Hi folks,
I have a question.
According to the feature list OJB, "classes can be mapped to an arbitrary number of JDBC sources".
I think this description is not very accurate. A long time ago we allowed to have different JDBC connections defined per class.
But we dropped this feature, because it involved complex problems.
For example it required us to provide a proper 2 phase commit across multiple databases.
The current solution is much simpler. A PersistenceBroker instance works with a dedicated Jdbc connection identified by a jcdAlias in the repository.xml.
So it is possible to work with one Broker for database A and with a second broker against database B.
So it's still possible to persist objects to different databases. But the management (e.g. 2phase commit) must be implemented by user code.
I read this to mean that I could define a class descriptor so that it could be associated with a specific jdbc-connection. Therefore class-descriptors with foreign key relationships would resolve across different JDBC connections and end up with the following kind of SQL querystring:
SELECT remoteHost.table.field, localHost.table.field FROM localHost.table.field INNER JOIN remoteHost.table ON localHost.table WHERE remoteHost.table.field='foo'
Am I asking for too much?
yes :-)
cheers, Thomas
regards,
Simon Allaway
--------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
--------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
