Multidatabase systems respond to the need of organizations to support applications that require information maintained by several autonomous and possibly heterogeneous database systems. A fundamental requirement underlying Multidatabase systems is the preservation of the autonomy of the individual database systems. However, autonomy requirements cause problems in maintaining traditional database consistency in these systems, the reason being that autonomy and consistency are conflicting requirements. Attempts to strike a balance between these two requirements have focused on new correctness criteria. However, very little analysis has been done with respect to (a) the semantics of autonomy requirements and (b) their implications for both consistency requirements and implementation considerations. The goal of this research is to systematically analyze autonomy and consistency by applying a uniform specification technique to express autonomy requirements and correctness criteria, thereby explicitly showing their relationships and identifying the tradeoffs between them. By understanding these tradeoffs and their effects on different parts of a database system, this work will help in the development of Multidatabase systems and will have an impact on the integration of other systems in which autonomy and consistency are requirements.
