On Containment of Conjunctive Queries with Negation

Abstract. We consider the problem of query containment for conjunctive queries with the safe negation property. Some necessary conditions for this problem are given. A part of the necessary conditions use maximal cliques from the graphs associated to the first query. These necessary conditions improve the algorithms for the containment problem. For a class of queries a necessary and sufficient condition for containment problem is specified. Some aspects of time complexity for the conditions are discussed.

• Type: Conference
• Year: 2009
• Where: ADBIS
• Authors: Victor Felea
• Keywords: ADBIS 2009, Containment Problem, Database, Necessary Conditions, Safe Negation Property