In this paper, it is suggested an approach and a design pattern for developing object-oriented models that need to be persistent, including the databases of moderate size, with using only the standard C++ and its file storage facilities, and without using specific C++ dialects or any support of external libraries providing the persistence. Objects of the model may be of a great variety of types, belonging to a complex class hierarchy, and are considered to be of rather general structure, containing both pointers to any other model's objects and dynamically allocated arrays of various types. The main idea consists in that all types involved are considered as classes derived from the unique base class with the minimal common interface. Classes' objects are allocated dynamically, and the pointers are kept in the model's base-class pointers container, which provides sorting, searching, and changing the objects kept. The objects' serialization, reading, and management is implemented with using the virtual functions, list of type names, and object factory technique.