I'm going to make an application that will be given data to put in a database. The data will for the most part be the same, but the way it is formatted will vary a lot (could be in anything from text files to .xls to .doc).
I'm not a very experienced developer, but I can see some potential issues and I want to minimize them.
First off I have decided to use the DAO pattern, so that I can easily support new file formats or file suddenly formatted in different ways.
What I really wonder about though, is how I should manage the data itself within my application. I'm thinking that the database DAO should have models representing each table of the database with the same relations between them, to make the uploading process easy. But should the filesystem DAO's have to use the same models? I can imaging that when the database changes, the change will suddenly propagate throughout the entire system, all DAOs and models alike. And that is obviously a bad thing.

I'm a little bit tired and out of time. Will update with what ever questions you have.

Thanks!