Re: Mapping classes to multiple data sources

[Wayne Kidd <wa...@rdlogic.com>]

I am trying to use the multiple datasources in the way of the current 
solution.  That is, I have 2 jdbc connections, each of them has a full 
set of the same tables.  Therefore, only the jcdalias and its parameters 
are different.  It turns out that they are schemas in the same instance 
of Oracle.  Therefore 1 of the logged on users has USER1.TABA and the 
other has USER2.TABA.  The Class Descriptors are precisely the same 
(since we do not specify the Schema name in the Class Descriptor of 
TABA.  This actually works up to a point.  I am able to get an object 
from USER1.TABA with key X.  I can also get an object from USER2.TABA 
with key Y.  However, if I try to get an object from USER2.TABA with key 
X, I am returned the object even if it does not exist in USER2.TABA.  I 
suspect this is due to cacheing, but I have not yet been able to prove 
that.  I would rather not have to deploy the thing as 2 separate web 
apps (not even sure that would solve the problem - maybe the cache is 
container-wide).  Does my speculation make sense (and if it does not, 
what might be the real problem).


Thanks in advance

Wayne


> 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.




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