The book contains educational and practical materials devoted to the study of the interaction of client applications with databases. The design of the server part is considered from the point of view of developing relational database structures and programming their objects in the SQL language in the MS SQL Server database. The development of the user interface is considered on the basis of platform technologies . Net in MS Visual Studio environment. Intended for full-time and part-time students of the directions 09. 03. 01 "Computer Science and Engineering", 02. 03. 03 "Mathematical support and administration of information systems", 38. 03. 05 "Business Informatics" in the disciplines "Data Bases and Client-Server Applications", "Client Application Programming", "Distributed Systems", as well as students of all forms of training direction 38. 04. 04 "State and municipal administration" .