A Specialization on the Remote Database Access

Abstract

The RDA (Remote Database Access) standards support the interworking between an application program in one open system and a DBMS in a remote open system. The Generic RDA standard defines the common aspects of a class of RDA applications, and a Specialization standard describes a specialization for a particular type of DB in the class. The RDA model describes RDA via clienVserver relationship. The services of RDA are grouped into five categories: Dialogue Management, Transaction Management, Control, Resource Handling, Database Language. The server execution rules are defined for each service. The Basic Application Context and TP Application Contexts are used to perform the necessary set of RDA services. RDA Specialization defines any required constraints on the permissible parameter values for each service. Also, it defines additional entities and their attributes on the Dialogue State Model. For each server operation, additional constraints are defined. As the basic step of constructing prototype RDA for a subset of database languages, two RDA service user interfaces were designed and necessary functions and parameters were defined. First, to fill the gap of functionalities between the RDA client and the RDA Communications Service, one RDA Client Interface model was designed. Second, an RDA Server Interface model which contains necessary library functions and parameters to send an RDA indication and receive the response for it was designed to fill the gap of functionalities between the RDA server and the RDA Communications Service. Also, a set of Generic Object Management Library functions for the RDA server as one possible implementation model was defined and the functions for the RDA server to interface with SOL Server Interface for the RDA specialization were refined and added. The internal execution of RDA operation according to the RDA server rules were explained by using the functions of Generic Object Management Library for the RDA server. All the functions were designed by the object-oriented concept. So, this model can be modified conveniently and implemented easily to accommodate other types of database languages by the object-oriented languages because of functional modularities of library functions.