Thanks for the term "Transparent Application Failover" I searched for it in the Oracle docs and found lots of references. They say that in Oracle 8i Enterprise Edition, we can apply the same principles for Replicated systems as for OPS, ie change the TNSnames.ora file and add some failover specific information in there. Ofcourse as you said, the client has to be written to support it, as for eg, DMLs will not be moved over to the failover database if they have not been commited. The application has to reissue them.

This definitely sounds promising, my next task is getting it to work !!