What do you mean “flatfile”, strictly speaking, an Excel spreadsheet is a type of flatfile. You need to provide much more information if you want help.
A “Flat-File” is a file in which data is formatted in plain-text, usually with some kind of delimiter (tab, comma, etc.).
If you don’t know what half the question is talking about why bother to respond? I was really looking for a helpful answer because I know what a “flat-file” is and I had the same question…the top answer here is disappointing to say the least…jeez