The free object-relational database management system is a good alternative to other databases. PostgreSQL provides flexible access to databases, their organization, storage and management. The database has powerful and reliable transaction and replication mechanisms. PostgreSQL is characterized by inheritance and easy extensibility. The control system supports downloading of C-compatible modules. This is a popular object-relational database management system that is used in such large companies as Alibaba, Huawei, Instagram, Skype and others.