You can create an entity in your domain model that matches the oracle table. Then you can use the database connector module to retrieve the data from your external database. Then you can build a page to manage all the data, for basic info on how to do that I would look at the learning modules here
A quick way to generate a basic overview page is to use the "generate overview" functionality in the modeler. If you right click your entity you can see this option and it will generate some basic pages for you.
Once you have your page built, you can add a microflow button inside the dataview of that page. Now in your microflow you can use a parameter to pass the object of that page to your microflow. From there you can send that data back to your external database.
Hope this helps!