Over on Devlounge you can find out some great tips, tricks and tutorials on how to create a plugin that can use a databse, be it your own tables, and/or WordPress’ own.
When you are writing a plugin, you will inevitably have to store variables in a database and retrieve them. Fortunately WordPress makes data retrieval simple with options and a database object. This post will cover storing and retrieving data from a WordPress database.
This is just part of a great WordPress Plugin development series going on at Devlounge.