The chase revisited

We revisit the classical chase procedure, studying its properties as well as its applicability to standard database problems. We settle (in the negative) the open problem of decidability of termination of the standard chase, and we provide sufficient termination conditions which are strictly less over-conservative than the best previously known. We investigate the adequacy of the standard chase for checking query containment under constraints, constraint implication and computing certain answers in data exchange. We find room for improvement after gaining a deeper understanding of the chase by separating the algorithm from its result. We identify the properties of the chase result that are essential to the above applications, and we introduce the more general notion of an F-universal model set, which supports query and constraint languages that are closed under a class F of mappings. By choosing F appropriately, we extend prior results all the way to existential first-order queries an...

• Type: Conference
• Year: 2008
• Where: PODS
• Authors: Alin Deutsch, Alan Nash, Jeffrey B. Remmel
• Keywords: Classical Chase Procedure, Database, Extended Core Chase, Incomplete Standard Chase, PODS 2008