Relational data bases are a novel but very dynamically developing field of knowledge. The article contains a review of the available and most popular systems of management of data bases. Its introductory part describes the rules concerning the relational model of data base elaborated by an American mathematician E. F. Codd and a short description of the SQL language being a standard of the structural language of questions increasingly more commonly used in the systems ,of management of relational data bases today. The core of the article are short presentations of the following data bases: Oracle 5.1,Ingres 5.0, Informix SQL and 4GL, SQLBase, Btrieve 4.1. and XQL 1.0,XDB II, SCO Integra, dBASE IV, Paradox 2.0, FoxBASE. In the final part of...