You should expect to see very simple examples of how you can utilize OOP to interact with a database in Python.
For the ease of the user to not have to connect to a real database and have a learning curve of the, I created a fairly straightforward, yet limited, "database" that has all CRUD functions. This will help you get the feel of interacting with a database with simple crud functions.
If you want to learn more on how to connect to a database, I would suggest SQLite, but you can choose whatever makes sense with your needs. I just prefer being able to have an interface of the database I am working with in my local file directory.
If you want to learn more about how to interact with a database in Python. I would suggest learning an ORM. A highly used ORM that I have used for years, is SQLAlchemy. This has a fair learning curve, and will help you learn the fundamentals of ORMs.