Integration of Aggregation Constraints

To obtain a correctly integrated schema which corresponds to the modeled real world, integrity constraints have to be considered in the schema integration process. Previous publications on this area focused on the integration of object constraints as well as certain class constraints like uniqueness constraints. In this paper, we discuss the ability to integrate aggregation constraints which are integrity constraints that are based on aggregate functions like min, max, avg, sum, and count. For this purpose, we define two fundamental integration properties: decomposability and composability of integrity constraints. By means of these properties we are then able to conclude whether an aggregation constraint can be integrated or not