ну sqllite, какую же еще)
realm
Dmitry
Artem
Student
Maksym
Sergey
.
Sergey
.
Izya
Sergey
Sergey
.
Izya
.
.
.
Astar
Yank
Mike
Astar
Astar
Mike
Mike
Dmitry
Astar
Mike
Astar
Mike
Mike
Dmitry
Astar
Astar
Daniel
Dmitry
Daniel
Dmitry
Astar
Izya
Dmitry
Astar
Alina
Dmitry
Mike
Daniel
Astar
Dmitry
Daniel
Dmitry
Mike
Mike
Astar
Dmitry
Mike