As to a systematic approach - I approach database testing (currently about 90% of what I do is database testing - though it is all manual) like I approach any other testing.
That is, plan to validate the requirements and verify the design (when it is available). Some of the projects are so different from others that there would not be a system that would effectively cover each of them.
My personal opinion is that test "strategizing" and planning is best done manually. Though it is reasonable that that manual process will direct for automated events to occur.
Test Cases - for database or for functional testing will be specific to the application/product being tested and for many of us this is proprietary information belonging to the company that we work for.
Also I see that you are a student - are you attempting to complete an assignment with someone else providing the work for you?
You would probably learn more if you asked for feedback on something that you have created yourself.
I have not failed. I've just found 10,000 ways that won't work" --Thomas Edison