This week's book giveaway is in the OCAJP forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide 1Z0-808 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
Depends on the database really. Most databases keep the information about the fields and tables in a special table, so you can just issue a query on that table. Can you tell us a little more about what sort of setup you are working with?