I have used Silk Test to make queries and manage data for several DB and it works excellent, however, I have used it because I already have this tool, since Silk Test is not only for back-end testing I guess it could be a cheaper tools or maybe make your own tools like Corey_G could be a good approach.
Agreeing with Joe S. (which I always do because he knows his stuff), there are multiple ways and tools to do this type of work.
For MS-SQL Server (7.0 and beyond) I have written custom queries and stored procedures to extract data from my test database. These along with Jobs and Data Transformation Services packages have helped me "automate" my database testing. This is more of a homegrown solution and a cheap one in comparison to the tools, but effective.
It all depends on which tool/method you choose to solve this problem. Good luck.