A New Algorithm for the Containment Problem of Conjunctive Queries with Safe Negation

Abstract

Many queries about real databases havea particular form, e.g., the negated part consists ofone single literal or they contain just a single binaryrelation, etc. For a particular class of queries, it isuseful to construct algorithms for the containmentproblem, that are better than those for the whole classof queries. The paper is about the problem of querycontainment for conjunctive queries with safe negationproperty. A new algorithm to test the containmentproblem of two queries is given. Several aspects ofthe time complexity for the proposed algorithm arespecified. From this point of view, the new algorithmproves to be better than the previous for some classesof queries.