How do you test whether a database in updated when information is entered in the front end?

It depend on your application interface..

1. If your application provides view functionality for the entered data, then you can verify that from front end only. Most of the time Black box test engineers verify the functionality in this way.

2. If your application has only data entry from front end and there is no view from front end, then you have to go to Database and run relevent SQL query.

3. You can also use database checkpoint function in WinRunner.