The Impedance Mismatch in Light of the Unified State Model

Abstract

In this paper we discuss the misunderstanding that have arisen over the years around the broadly defined term of the object-relational impedance mismatch. It occurs in various aspects of database application programming. There are three concerns judged the most important: mismatching data models, mismatching binding times and mismatching object lifecycle. This paper focuses on the data model mismatch. We introduce the common state theory, i.e. a unified model of objects in popular programming languages and databases. The proposed model exploits and emphasizes common properties of all these objects. Using our model we demonstrate that there are notably more similarities than differences. We conclude that the impact of the mismatch of data models can be significantly reduced.