Hi,
I am supposed to add some extra functionalities or screens to an Oracle Application. Now this is totally new to me. I just did some Google'ing to know what are Oracle applications actually. Please give me some good references or tips as to how I can start, or where I should start. What all should be the pre requisite knowledge I should be having before starting of with this? Any references useful for me on this regard, the Oracle Application ?
By Oracle Application you are referring to a database GUI or a custom application with a Oracle backend?
We need a little more info I think 
It is a custom Oracle HRMS. And what we need to do is add a link in the existing application that will take us to the added functionlities for the same Oracle application. What I mean is the link will show us a web page where we have access to all extended functionalities , using the same Database that the Oracle HRMS has already been using. The complete dataset will be the Oracle Database for the HRMS already being used. Let me know if further info is required.