A tuple t1 of relation R subsumes tuple t2 of R, with respect to a query Q if for every database, tuple t1 derives all, and possibly more, answers to query Q than derived by tuple ...
Abstract. We present a semantics and answer set programs for relational peer data exchange systems. When a peer answers a query, it exchanges data with other peers in order to supp...
— Autonomous index management in native XML DBMSs has to address XML’s flexibility and storage mapping features, which provide a rich set of indexing options. Change of worklo...
It is known that the composition of schema mappings, each specified by source-to-target tgds (st-tgds), can be specified by a secondorder tgd (SO tgd). We consider the question of...
Tree based indexing structures like -trees, ·-trees, Bitmap indexes and Ê-trees have become essential for getting good performance when accessing vast datasets. However, most dat...
Yannis Kotidis, Yannis Sismanis, Nick Roussopoulos