Database testing.

Hi,
My questions are regarding the way you are doing tests to your database.
1. Can you explain in general the method you test the database
engine.
2. Are you doing testing for data integrity?
3. Are you using a special tool for testing? If yes, is it
propriety for you or off the shelf?
4. What is the ratio between people doing development to people
doing testing or between development time to test time.

Some background on where these questions came from.
My name is Niv Cohen and I'm working for SanDisk.
We developed a small embedded database for our needs and we feel the
luck of expertise in the area of testing this module.
We by no mean going to sell this as stand a lone database.

Thanks a lot,
Niv