During my early Pen Testing days I took a liking to databases, probably because I did a fair amount of Oracle DBA work at NASD/NASDAQ (now FINRA) during my Unix sys admin days.
Anyways, my presentations are a culmination of my research, testing, and desire to ethically hack databases during consulting engagements.
A number of presentations can be found on my World Tour page. The presentations cover Oracle, SQL Server, and a little dabbling in MySQL and DB2.
Many thanks to the Litchfield brothers, Pete Finnagan, and Chip Andrews (we still need to meetup at Taco Mac for a brew! :)
My most recent Database Pen Testing Presentation from ISSA Charlotte Conference 2008