Hi Andrus,
Thanks for your reply... Of course, this is almost exactly what Cayenne
is for. I erred in the question I was asking, unfortunately, so I will
ask it properly this time... =). I really just have a minor question to ask:
My two database schemas are *almost* identical, but not quite. The MySQL
database creates primary keys on certain tables by using an
AUTOINCREMENT column. The Oracle database creates primary keys on the
equivalent tables by using a custom sequence. Is there any way for me to
change the primary key generation strategy depending on which DBMS is in
use? Or will I have to choose a strategy that works equally on both
Oracle and on MySQL (ie, switch to using the default strategy?).
I would ideally like to continue using the auto-increment columns on
MySQL, since that intuitively seems like the most efficient method to
me. I have experimented with customizing the mapping.xml file at runtime
based on which type of database I'll be using, before making any calls
to cayenne, that seems to work. But it's also pretty hacky, and will
make maintenance more painful.
Thanks,
Mike Shea.
Hi Michael,
Cayenne will detect the database type automatically on startup and use
the right adapter. So yes, use JNDI to abstract connection
information, beyond that no need for any extra tricks. You generic
Cayenne mapping will just work regardless of the db type.
Andrus
On Oct 20, 2008, at 11:42 AM, Michael Shea wrote:
Hi guys,
I am working on a project in which I have to support multiple
database types. They do not have to be supported simultaneously - I
need my program to be able to run whether I am using an Oracle
database or a MySQL database (the databases will have the same
schema), but the database type does not change at runtime.
I am wondering if there are any best practices or recommendations for
how to approach this problem. Currently, I am planning on simply
creating two sets of cayenne configuration files in different
directories (ie, a map.xml and a cayenne.xml file), and just adding
one or the other of these directories to the classpath, depending on
some initial configuration parameters that tell me what type of
database I'm accessing. The datasource is defined via JNDI.
Does anyone think that this is a good idea or a bad idea, or have a
better way of doing this? =) I am using Cayenne 2.0.4.
Thanks!
Mike Shea.
