This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
some databases have the ability to ignore duplicates. this would allow you to simply insert everything adn let the database do the work of deciding if it is already there. another option would be to insert all the csv records into a table, and then use sql to only insert the records in the real table that don't already exist there.