Websphere doesn't provide out of box feature of data base authentication. This is really annoying if you want your web/ear applications deployed in WAS to be authenticated against the relational databases such as oracle, sybase, etc. Interestingly weblogic provides very good feature of configuring SQL authentication provider with Relational Database. It uses data source to configure. I have myself configured & authenticated successfully with Oracle in Weblogic. More info on that in feature.
But Websphere you need to write custom code for SQL authentication. You cannot use other WebSphere Application Server components, for example, data sources, to initialize the custom registry because other components, like the containers, are initialized after security and are not available during the registry initialization. A custom registry implementation is a pure custom implementation, independent of other WebSphere Application Server components. confusing? thats the way it is.
So I have custom code which authenticates with Oracle. This works OK. Obviously I also need to create the database schema for storing user/group/role information.
I wont be able to publish the code on the internet. But I can share with anyone if they are interested.