A unified apriori-like algorithm for conjunctive query containment
Fang Wei, Georg Lausen · 2008
The design of containment checking algorithms for conjunctive queries with arithmetic comparisons and safe negations (CQ­s) is fundamental to many database applications. However, it is a challenging task due to the intractability of the problem. Existing algorithms are either computationally too expensive, or capable to deal with only a fragment of these extensions.