Right, if the application is running in the cloud itself you don't need the "connectors". Thought you would run it on-premise.
For your case you can check Adding Persistence with JDBC. As described in the example you have to define a resource reference in the web.xml. To define the db/schema which should be used to have to do the data source binding. It can be done for example in the Cloud Cockpit (go to your deployed Java application, select it and do the binding in menu "Data Source Bindings").
Regards,
Florian