I wouldn't say there are much differences in the JDBC driver regarding performance (talking about pure JDBC driver). The biggest difference should happen in the DB itself.
For Oracle there exists also an OCI driver (native) which can be called from
java. This driver increases performance immens.
The other thing is also which machine are you running your db. Oracle needs a bigger box then MS SQL Server (Hope you really meant this with SQL Server).
[ September 24, 2003: Message edited by: Oliver Refle ]