Discusses the use of information processing as a tool for formalizing and implementing different aspects of database systems in a uniform manner. By means of knowledge information processing and logic programming (PROLOG), high-level query languages are implemented using the same data management software. Using PROLOG in a database system results in reduced costs and increased flexibility of implementation and application. Program languages implemented here in PROLOG are ML based on ISBL, EL based on SQL, and PL based on QBE.