Data Driven Testing for a database web application
First of all you need to create Equivalence Classes that cover most of your input dataset.After that you can simply run your selenium/JMeter tests with the test data created.
You just need to create single test script and populate the test data in excel or CSV sheets to perform data driven driven testing.
Have a look a jBehave.
It's a BBD tool that can drive selenium and supports sets of input test data.
I've used it and it works well. You'll need patience to get through the glue code, but once you're out the other side you'll be glad you persevered.