In terms of efficiency, the best advice I can give is to construct your SQL statements carefully. Retrieving all the rows and then filtering for a certain section using Perl is very inefficient. Let the database worry about section for you by only SELECTing where section is the one you're looking for.

It sounds like you could use a crash course in database design - it's too complicated to get into here. A quick Google search turned up a W3Schools SQL course but it doesn't really get into the design aspects of databases. I also turned up a howto article on Lycos' "webmonkey" site which looks much more promising.

Best of luck.

--
Grant me the wisdom to shut my mouth when I don't know what I'm talking about.