I tried to wash my past sins of not attending to lectures properly by listening to some university lectures today. Out of jokes, being a DB practitioner I found it to be refreshing again to listen to the theoretical side of databases again.
If you are really really busy at least listen to the second lecture on relational algebra at http://www.db-class.org/course/video/preview_list. Take my word on this if you are a programmer its worth listening to this. If you are even more interested, you can register for the online course too! btw its from Stanford! Enjoy!