Many advanced applications need to access and integrate resources and services provided by distributed, autonomous, and heterogeneous systems. Building an integrated system to provide uniform access and cooperation among these underlying heterogeneous systems is both an increasing necessity and a formidable challenge. An important component of such a complex integrated system is a language that would serve both as a data definition and as a data manipulation tool. Special requirements are posed in the instance of an integrated system which includes database systems among its components. In this paper, we present the necessary constructs that an object-oriented programming language should provide for being adopted as the language of the integrated system in such a setting.