At the time of the spread of information and communication technology security is one of the most important factors affecting the business and the private world . This thesis deals with all the factors for a successful and safe business environment, stresses the difference between a secure closed network and secure network outside the system. The paper is based on the description and understanding of all the factors that make up the network and shows the role of databases within it . It addresses the structure, architecture and the relationship between client and server, connects the main types of servers with their roles within the system. It also states the importance of virtualization as the most powerful tool for remote work and support for all users, which allows domain networking at home or even other domain networks. In the last part of the thesis we review the use of databases such as Oracle or PostgreSQL and their comparison from the field, in which are explained and compared the advantages and disadvantages of both systems.