Paper Info
Title
To Form a More Perfect Union (Intersection, Difference)
Abstract
The AQUA (16) query algebra allows user-defined equivalence relations as arguments to query operators that gen- eralize standard set operations. These predicates determi ne what objects are included in the query result, and the duplicates that must be removed. While an expressive enhancement, the use of arbitrary equivalence relations to decide set membership can result in sets with counterintuitive behavior, and therefore can m ake queries return unreasonable results. In this paper, we show that equality predicates assume two roles with respect to sets. Distinguishers differentiate between set members and implicitly give meaning to standard set properties such as set equality. Constructors determine which object from input sets contribute to the query result. The requirements of distinguishers and constructors differ. AQUA's set operators are problematic because they use constructors wh ere distinguishers are required. We propose alternatives to AQUA's set operators that address this limitation.
Year
Venue
Keywords
1995
DBPL
perfect union,equivalence relation
Field
DocType
ISBN
Counterintuitive,Equivalence relation,Programming language,Computer science,Set operations,Theoretical computer science,Operator (computer programming),Predicate (grammar),Query algebra,Adequate equivalence relation
Conference
3-540-76086-5
Citations 
PageRank 
References 
14
10.45
16
Authors
3
Name
Order
Citations
PageRank
Mitch Cherniack14128293.66
Stanley B. Zdonik291861660.15
Marian H. Nodine3368125.25