File processing vs. Data Base

[riccardoregina]

At this moment, the application works with files because of its low complexity. However, file processing is ... cumbersome, let's say.
Passing from File processing to a local Data Base could ensure maintanability during time.

Note: Loading a transaction history from file is a key feature as well as make the application update it. A Data Base should not supersede the role of files in this application: a Data Base should just help manipulate data.