[logback-user] How to set dialect for a DBAppender

I getting the following error, when I try to use a DBAppender: ch.qos.logback.core.db.DriverManagerConnectionSource@7d8a8ce2 - Could not discover the dialect to use. java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection at java.sql.SQLRecoverableException: IO Error: The Network Adapter could not establish the connection at  at oracle.jdbc.driver.T4CConection.logon(T4CConnection.java:419) How do I manually set the sql dialect to use, in the logback xml configuration file (ie- xml tag name to use, etc...), assuming I am getting a dialect error? Thank you Jeff