Databases and Permalinks

In the past I have developed stand-alone applications in PHP, but I am new to wordpress and have started creating a plugin.

I need to create a database for my plugin to use, is there a tutorial that explains how wordpress accesses the database, makes changes, echo’s information (as I need to present some of my data in tables).

Also I am looking for a tutorial how to use the permalinks.
You see I need the links to work as follows

Category Page: mysite.com/games/
Category->Product Page: mysite.com/games/gamesname/
Category->Product->Screenshot page: mysite.com/games/gamesname/screenshots/
Category->Product->Any Other pages page: mysite.com/games/gamesname/whateverhere/