Ok thanks for the advice again. I'm really just using XML files because I thought it would be cool and i'm fed up with using CSV files. I also want to learn something new and I thought this was a good reason to try. I do know all about SQL, i.e. linking Perl to MySQL, but I really don't want to have to rely on a separate RDBMS.
This SQLite thing looks pretty cool I will have a look at it. I'm not sure if I mentioned it before, but this is all part of my auction software. At the moment i'm storing everything in CSV files, it works fine, but i've been thinking about upgrading to a RDBMS like MySQL, but just haven't got around to it yet, perhaps i'll give SQLite a go instead.