create a loan application using C# & Oracle

Thanks Friends. i will meet you again.

I have to agree with Dave, the only way you can design such an app is by first talking with your client and see what they need to automate their loan business. You need to know how the business works inside out so do a little research. Why not start by going to the premises and see how things are done? You may need to study the documents used in the business so as to get an understanding of the input requirements.
After doing an analysis of the business take time to design the database in terms of the tables that you will need to such as : payments table and borrowers table(containing info about borrowers such as name,contacts etc) to name just but the bare essential tables . Set up the relationships well then design any queries that you may need.
When your database is in order sketch designs of how input and output will be handled by the application before doing any coding.There is nothing as bad as discovering you've left out something and fixing it. somewhere may cause chaos.
Armed with your sketches create the user interface (don't be concerned with nice graphics coz you can play with this after your app works). Show your designs to the client to see if they r ok with it before you start coding, after all,why code something that they don't like? If you get the green light do the code and finish off with polishing the interface.