If you are looking for a subject area for your project rather than a recommendation for which DBMS software to choose, try these steps:
1. Think of the things around you that you want to keep track of or keep organized. Bills you pay? Books or music you own? Vehicle maintenance you want to keep track of? Cooking recipes?
Once you've identified some of those things around you, here are some questions you should ask yourself:
2. Is the subject something I'm familiar with? For example, if you are a student, you probably understand how classes, students, professors and books all relate to each other. If you've never been a student (just for the example's sake) you may have a fuzzy understanding of those things.
3. Is there sufficient detail to make it a non-trivial project? For example, If you chose a phone list project and all you had were people names and phone numbers, you could solve it in one table with two columns. It's a trivial solution and not worth the effort.
Now, not knowing anything else other than that you don't have much experience with DBMS's, I hesitate to give more specific advice. Try these suggestions out and see what happens.
If I've misunderstood your request for help, accept my apologies and please post a clarification of what you're expecting.
If you're in one of those predicaments where cls.__private attributes just aren't enough since they can easily be accessed through inst._cls__private, and you need something a little more secure, here's ...