rapaport@ellie.UUCP (William J. Rapaport) (03/17/86)
UNIVERSITY AT BUFFALO STATE UNIVERSITY OF NEW YORK DEPARTMENT OF COMPUTER SCIENCE COLLOQUIUM HANS HERMANN BRUEGGEMANN Department of Computer Science University of Dortmund THE ONE-FLAVOR ASSUMPTION AND GAMMA-ACYCLICITY FOR UNIVERSAL RELATION VIEWS A universal relation view is a view on top of a relational database scheme. In a universal relation view, queries are expressed without mentioning relation names, and they are evaluated by using ``window'' functions. We discuss several design rules for database schemes suited for universal rela- tion views and formalize one of them, the One-Flavor Assump- tion. This assumption says that the real-world significance of any tuple of a window does not depend on the details of its construction. We prove a deep connection between data- base schemes satisfying the One-Flavor Assumption and so- called gamma-acyclic schemes. For such database schemes, we define the essence of join paths used in the universal rela- tion system DURST. For universal relation views based on such schemes, the DURST window functions are essentially optimized. Tuesday, March 18, 1986 3:30 P.M. Bell 338, Amherst Campus There will be a reception at 4:30 P.M., 224 Bell Hall For further information, call (716) 636-3181. -- William J. Rapaport Assistant Professor Dept. of Computer Science, SUNY Buffalo, Buffalo, NY 14260 (716) 636-3193, 3180 uucp: ...{allegra,decvax,watmath}!sunybcs!rapaport ...{cmcl2,hao,harpo}!seismo!rochester!rocksvax!sunybcs!rapaport cs: rapaport@buffalo arpa: rapaport%buffalo@csnet-relay bitnet: rapaport@sunybcs