I'm creating the game and wanted to use some database in it. I've choosen firebird. The problem is I cannot find ANY tutorial about using it via C++. I downloaded IBPP but also I'm unable to find any guide how to use it. Do you have any tutorials u could share with me? Also if other databases like Postgres are better or just easier to use in C++ then just let me know please. Thanks in advance.

Ask Google about "Firebird C++ API." It produces a number of links, including this one, which seem relevant.