A uniform methodology for extracting type conflicts and subscheme similarities from heterogeneous databases

Cooperative Information Systems have been proposed to allow a uniform acces s to heterogeneous data yet preserving their operational autonomy. They use global dictionaries defined on the basis of interscheme properties; these include nominal and structural properties, type conflicts and object cluste r similarities. Whereas in the literature a certain number of techniques ha s been proposed for deriving nominal and structural properties, few approac hes exist for detecting type conflicts and object cluster similarities. The type of an object indicates if it is an entity, a relationship or an attri bute; type conflicts indicate the existence of objects representing the sam e concept yet having different types. Object cluster similarities denote si militudes between portions of different schemes. This paper proposes an aut omatic, probabilistic approach to the detection of type conflicts and objec t cluster similarities in database schemes. The method we are proposing her e is based on considering pairs of objects having different types (resp., p airs of clusters), belonging to different schemes and on measuring their si milarity. To this purpose object (resp., cluster) structures as well as obj ect (resp., cluster) neighborhoods are analysed to verify similitudes and d ifferences. A number of examples shows the suitability of our techniques to effectively detect type conflicts and object cluster similarities. (C) 200 1 Elsevier Science Ltd. All rights reserved.