Simple answer to the question as written: Define database.
The minimal viable database accessed from C# is
Dictionary, although some may argue that it is
Object. These classes can be used from within Unity, and they can be serialized to and from a file on disk.
While we sometimes call libraries like SQLite databases, in reality they are just software libraries. Libraries almost always give you plenty of features you don't need, along with some features you do need, solutions to problems you never knew existed, and generally a lot of correctness. For example, any decent database library doesn't destroy your file if the application crashes while it was still writing to the file.
You could certainly argue either way in your case: use a
Dictionary and serialize it to a file (simpler), or use SQLite (likely more correct). Both options are "correct".