Skip to main content
Article thumbnail
Location of Repository

The Impact of Virtual Views on Containment

By Michael Benedikt and Georg Gottlob

Abstract

Virtual views are a mechanism that facilitates re-use and makes queries easier to express. However the use of iterative view definitions makes very simple query evaluation and analysis problems more complex. In this paper we study classical containment and equivalence problems for queries built up through simple unions of conjunctive queries and view definitions. More precisely, we determine the complexity of containment and equivalence for non-recursive Datalog. We show that the problem is much harder than its classical counterpart – complete for co-NEXPTIME. We then show that this remains true even with restrictions on the schema and queries in place. Finally, we isolate subcases that are more tractable, ranging from NP to PSPACE

Year: 2010
OAI identifier: oai:CiteSeerX.psu:10.1.1.173.5447
Provided by: CiteSeerX
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://citeseerx.ist.psu.edu/v... (external link)
  • http://www.comp.nus.edu.sg/%7E... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.